Search

There is an immense research interest in molecular hybrid materials posing novel magnetic properties for usage in spintronic devices and quantum technological applications. Although grafting magnetic molecules onto carbon nanotubes (CNTs) is nontrivial, there is a need to explore their single molecule magnetic (SMM) properties post-grafting to a greater degree. Here, we report a one-step chemical approach for lanthanide-EDTA (Ln = GdIII, 1; TbIII, 2 and DyIII, 3) chelate synthesis and their effective grafting onto MWCNT surfaces with high magnetic bistability retention. The magnetic anisotropy of an Ln-CNT hybrid molecular system by replacing the central ions in the hybrid complex was studied and it was found that system 1 exhibited a magnetization reversal from positive to negative values at 70 K with quasi-anti-ferromagnetic ordering, 2 showed diamagnetism to quasi-ferromagnetism and 3 displayed anti-ferromagnetic ordering as the temperature was lowered at an applied field of 200 Oe. A further analysis of magnetization (M) vs. field (H) revealed 1 displaying superparamagnetic behavior, and 2 and 3 displaying smooth hysteresis loops with zero-field slow magnetic relaxation. The present work highlights the importance of the selection of lanthanide ions in designing SMM-CNT hybrid molecular systems with multi-functionalities for building spin valves, molecular transistors, switches, etc. [ABSTRACT FROM AUTHOR]

Due to their unique properties, bi‐segmented systems are currently used in several technological applications such as sensing devices, high density magnetic data storage systems, spintronics and microelectromechanical components, among others. In this study, the magnetoresistance and magnetic properties of Ni–Fe bi‐segmented cylindrical nanodots in a broad range of diameters and heights are discussed. The power of the First Principles approach, as considered in the density functional theory formulation, is used to study the structural and magnetic relaxation effects, and atomistic simulations, through the Fast Monte Carlo methodology, are employed to explore the magnetoresistance and magnetic behaviors of these systems. By means of the magnetic hysteresis and magnetoresistance signals, convoluted magnetization reversal schemes are discussed. These effects take place depending on the size of the Ni and Fe components as a result of the interplay among exchange interactions and size and shape effects induced by dipolar interactions. Since size has become an experimental controllable parameter, due to the enriched phenomena, the effects discussed in these bi‐component systems are useful for the design and production of devices for technological applications with relevance beyond the observed in the more restricted single component systems. [ABSTRACT FROM AUTHOR]

The magnetic properties of layered nanowires (NWs) composed of alternating nickel and copper layers were studied. In such structures, magnetic properties are governed by several factors, such as the aspect ratio of alternating layers, the dipole interaction between neighboring layers within a single NW, and the interaction of neighboring NWs. NW arrays were formed by matrix synthesis. Nickel layers had a fixed thickness of 400 nm, and the thickness of copper layers varied from 25 to 300 nm. The magnetic characteristics of such NWs were studied in two states: in a matrix (integral magnetic characteristics determined by vibrating sample magnetometry) and for individual NWs (local magnetization visualized by magnetic force microscopy (MFM)). For NWs in a matrix, the hysteresis loops measured for two magnetic field directions became identical when the thickness of a Cu layer increased to 300 nm due to the weakening of dipole interaction between Ni layers inside NWs and the growing role of dipole interaction between neighboring NWs. In this case, the residual magnetization grew after a field parallel to the matrix plane was applied. The samples with a Cu layer thickness of 300 nm were studied by MFM. It was step-by-step demonstrated how the application of an external magnetic field led to magnetization reversal. Magnetization reversal in a pair of NWs was revealed to occur in two stages like in a two-phase system with two characteristic fields: Hc1 = 40–50 Oe for the formation of a pair with the opposite magnetization direction and Hc2 =160 Oe for complete magnetization reversal. The latter value was close to the coercive force for an array of NWs in a matrix. [ABSTRACT FROM AUTHOR]

It is widely known that antiferromagnets (AFMs) display a high frequency response in the terahertz (THz) range, which opens up the possibility for ultrafast control of their magnetization for next generation data storage and processing applications. However, because the magnetization of the different sublattices cancel, their state is notoriously difficult to read. One way to overcome this is to couple AFMs to ferromagnets—whose state is trivially read via magneto-resistance sensors. Here we present conditions, using theoretical modelling, that it is possible to switch the magnetization of an AFM/FM bilayer using THz frequency pulses with moderate field amplitude and short durations, achievable in experiments. Consistent switching is observed in the phase diagrams for an order of magnitude increase in the interface coupling and a tripling in the thickness of the FM layer. We demonstrate a range of reversal paths that arise due to the combination of precession in the materials and the THz-induced fields. Our analysis demonstrates that the AFM drives the switching and results in a much higher frequency dynamics in the FM due to the exchange coupling at the interface. The switching is shown to be robust over a broad range of temperatures relevant for device applications. [ABSTRACT FROM AUTHOR]

Organic spintronics is an emerging research field that offers numerous fundamental physics and has shown potential in future spintronic applications. The spin-polarized hybridized interface formed at the ferromagnet (FM)/organic molecule (OM) interface is called the "spinterface." It has been found that the spinterface helps to reduce the well-known impedance mismatch issue in spin valves, enhances spin-polarization of the effective FM electrode, and aligns the molecular levels for easy spin transport. High magnetoresistance (MR) of ∼ 400% has been observed at low temperatures (∼10 K) for OM-based spin valves. However, the MR value at room temperature for such OM-based spin valves is low (∼10%) due to the complex nature of the FM/OM interface. During the last decade, much attention has been devoted to understand the nature of FM/OM interface for tailoring spintronic device functionalities. In this context, the role of spinterface on the global magnetization reversal, magnetic domains, and magnetic anisotropy in FM/OM systems becomes very important. Furthermore, it is also essential to understand the impact of crystallinity and thickness of FM on the induced moment in the non-magnetic OM in such heterostructures. Here, in this brief review, we give our Perspective on the progress and future challenges of the role of spinterface on various magnetic properties in FM/OM systems. Furthermore, we also discuss the recent observation of spin pumping in FM/OM systems where the OMs exhibit reasonable spin–orbit coupling. This shows the potential of OMs for spin–orbit torque-based physics and applications. [ABSTRACT FROM AUTHOR]

Magnetization reversal mechanism and stable remanent states of truncated conical nanowire of high aspect ratio are examined using micromagnetic simulation tool. The length of nanowire is fixed at 1 μ m, while its base radius R is varied from 50 to 10 nm and top radius r is varied R - 10 nm to R - 5 nm. The axial magnetization reversal proceeds predominantly through domain wall motion which is hindered as the tapering of the conical nanowire is increased. At remanence, a homogeneous magnetization persists throughout the nanowire except at the ends. Vortex states appear at both the ends in case of nanowires close to cylindrical shape, whereas a flower state of magnetization is exhibited at the tapered end if r is as small as ≤ 20 nm. Control of magnetization reversal through propagation of domain wall can be observed as tapered end with flower configuration successfully restricts the movement of domain wall. Expressions for total energy density of both vortex-vortex state and vortex-flower state are constructed, and the obtained values are compared with homogeneous configuration to understand the extent of stability. The transition of remanent state is successfully obtained by energy calculations. Angular dependency of coercivity shows the existence of a critical angle above which the coercivity follows Stoner–Wohlfarth model. Below the critical angle, the coercivity mechanism is explained by Kondorsky model if R is large, whereas a modified Kondorsky model is applicable for small base radius. [ABSTRACT FROM AUTHOR]

A squarate (sq) bridge was applied to heavy lanthanide (Ln) complexes for possible development of high-performance single-ion magnets (SIMs). A selective synthetic method for lanthanide squarate hydrates [Ln2(sq)3(H2O)8]n (abbreviated as Ln-sq) has been established, where Ln stands for Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. As the crystallographic analysis clarified, they all form a bilayer polymeric structure, which is isomorphic to known Eu-sq and Tb-sq. The coordination structures are described as an almost ideal square antiprism with D4d symmetry. Frequency-dependent susceptibility was recorded in alternating-current magnetic measurements for Ln = Tb, Dy, Er, Tm, and Yb. In particular, as for less studied Ln-based SIMs, the effective magnetization-reversal barriers, Ueff/kB = 21.4 ± 0.4 K (in a bias field of 1800 Oe) and 57.0 ± 0.4 K (400 Oe), were characterized for Tm-sq and Yb-sq, respectively, according to the Orbach-type relaxation mechanism plus a direct or the Raman mechanism. The barrier found for Yb-sq is the highest among those for all the compounds investigated here, and also regarded as one of the largest values for the Yb-based SIMs known so far. The complete-active-space self-consistent-field (CASSCF) calculation was applied to Tm- and Yb-sq. The ground doublet states with mJ = ±6 for the Tm3+ ion and mJ = ±7/2 for the Yb3+ ion were reproduced. [ABSTRACT FROM AUTHOR]

Seeking the magnetic heterostructures with large current-induced torque efficiency is currently one of the core hotspots in spintronics. In this work, we report the large and composition-dependent damping-like (DL) torque in the structure consisting of light metal Cr and Ti layers and a ferrimagnetic Tb–Co layer. The DL torque efficiency in the structures reaches a maximum (around −0.55) as the Tb content in the Tb–Co layer is in the range of 0.15–0.18. This composition-dependent behavior is different from that observed in the usual heavy-metal/ferrimagnetic structures. We also demonstrated the efficient current-induced magnetization reversal in these structures with a low threshold current density down to 8 × 10 10 A / m 2 . In comparison, only very low efficiency values of −0.06 and −0.086 are obtained in the Ti/Co/Cr and Ti/Tb–Co/SiN control samples, respectively, suggesting that the large DL torque in the Ti/Tb–Co/Cr structures may originate from the orbital Hall effect in the Cr metal. By fitting the Cr layer thickness dependence of the torque efficiency with a simple orbital current diffusion model, we obtained an effective orbital Hall angle of − 0.57 ± 0.02 for the Ti/Tb0.85Co0.15/Cr samples. This work demonstrated the possibility to enhance the orbital torque effect by using the magnetic layer containing the element with strong spin–orbit coupling. [ABSTRACT FROM AUTHOR]

Bilayers of an amorphous CoFeB ferromagnet coupled to an epitaxially grown IrMn antiferromagnet, whose anisotropy is fourfold symmetric, are modeled to study the angular (φ) dependence of magnetization reversal mechanism and exchange bias behavior, based on a modified Monte Carlo method. It is found that positive and negative exchange-bias field (HE) maximum values appear in the antiferromagnetic easy-axis directions, and the HE zero-value transition/return points exist in the antiferromagnetic hard-axis directions. Furthermore, the value of HE(φ) is well fitted by considering cos3φ/sin3φ terms with larger or comparable coefficients as compared to the first-order terms in the Fourier expansion. Finally, the microscopic spin configuration results evidence these phenomena originating from the tailoring of antiferromagnetic spins by simply rotating the field-cooling direction between antiferromagnetic easy- and hard-axis directions. We open an exchange-bias mode governed by antiferromagnetic fourfold anisotropy and propose a method to precisely detect antiferromagnetic higher-order anisotropies on an exchange-bias support. [ABSTRACT FROM AUTHOR]

The saturated magnetization (mtot) and the Gilbert damping constant (α) are the two key factors that determine the critical current density of the magnetization reversal in the spin-transfer-torque magnetic memory devices. Here, this study demonstrates the efficient modulation of these two parameters by tunning the composition of the Heusler Co3–xFexAl thin films, utilizing the x-ray magnetic circular dichroism technique and ferromagnetic resonance measurements. With the increase in Fe concentration, the mtot shows a downward trend mainly resulting from the decrease in Fe local magnetic moment instead of Co. On the other hand, the ultralow α decreases from 0.004 to 0.0012. This has been attributed to the reduction in the spin–orbit coupling, which is corroborated by the decrease in the orbit-to-spin moment ratio. Our findings add a building block for the Heusler compounds with tunable Gilbert damping and appropriate magnetization and show great potential in spintronic applications. [ABSTRACT FROM AUTHOR]

The present paper presents a thorough study of the ground state magnetic properties of the spin-one mononuclear nanomagnet mer-[V(ddpd) 2 ][PF 6 ] 3 , with the V 3 + center exhibiting a distorted octahedral coordination. The theoretical analysis is based on a multiconfigurational, self-consistent approach that effectively parametrizes the total energy spectrum of the considered coordination complex via exact diagonalization. We provide a comprehensive discussion for the obtained zero-field and field-dependent fine structure of the ground state along with the ensuing crystal field splitting of the 3d orbitals. Furthermore, we report the results for the low-field susceptibility, magnetization and the corresponding reversal dynamics, finding good agreement with the experimental data reported in the literature. The calculations show considerable zero-field splitting and strong field-dependent orbital unquenching underlying the occurrence of a field-induced full profile magnetization reversal barrier. [ABSTRACT FROM AUTHOR]

High-performance Nd-Fe-B-based rare-earth permanent magnets play a crucial role in the application of traction motors equipped in new energy automobiles. In particular, the anisotropic hot-deformed (HD) Nd-Fe-B magnets prepared by the hot-press and hot-deformation process show great potential in achieving high coercivity due to their fine grain sizes of 200–400 nm, which are smaller by more than an order of magnitude compared to the traditional sintered Nd-Fe-B magnets. However, the current available coercivity of HD magnets is not as high as expected according to an empirical correlation between coercivity and grain size, only occupying about 25% of its full potential of the anisotropy field of the Nd2Fe14B phase. For the sake of achieving high-coercivity HD magnets, two major routes have been developed, namely the grain boundary diffusion process (GBDP) and the dual alloy diffusion process (DADP). In this review, the fundamentals and development of the HD Nd-Fe-B magnets are comprehensively summarized and discussed based on worldwide scientific research. The advances in the GBDP and DADP are investigated and summarized based on the latest progress and results. Additionally, the mechanisms of coercivity enhancement are discussed based on the numerous results of micromagnetic simulations to understand the structure–property relationships of the HD Nd-Fe-B magnets. Lastly, the magnetization reversal behaviors, based on the observation of magneto-optic Kerr effect microscopy, are analyzed to pinpoint the weak regions in the microstructure of the HD Nd-Fe-B magnets. [ABSTRACT FROM AUTHOR]

The synthesis of REFe0.5Cr0.5O3 (RE = La, Y) using the sol–gel method is focused and their structural differences are investigated. The results of X‐ray diffraction show that the change of ion radius at position A leads to varying degrees of octahedral distortion and spatial group structure. The scanning electron microscopy analysis reveals micron‐level particles with clear boundaries, while energy‐dispersive X‐ray spectroscopy and room temperature Mössbauer spectra indicate the presence of Fe/Cr clusters in the sample and the transitional valence of iron. Disorder in the B position leads to a saturation moment that is lower than the theoretical value. The thermomagnetic profile shows a reversal of magnetization due to the interaction between the single‐ion magnetic anisotropy and the antisymmetric Dzyaloshinskii–Moriya (DM) interaction, with a broader peak is observed due to cluster formation. The difference in negative magnetic field is due to the difference in net magnetic moment caused by different DM intensities. [ABSTRACT FROM AUTHOR]

We report here the results of micromagnetic simulations of square artificial spin ice (ASI) systems with defects. The defects are introduced by the misaligning of a nanomagnet at the vertex. In these defective systems, we are able to stabilize emergent monopolelike state by applying a small external field. We observe a systematic change of dipolar energies of the systems with varying misalignment angle. The fields at which the emergent monopoles are created vary linearly with the dipolar energies of the systems. Our results clearly show that the magnetization reversal of the ASI systems is intricately related to the interplay of defects and dipolar interactions. [ABSTRACT FROM AUTHOR]

Spin Hall magnetoresistance (SMR) provides an effective tool to probe the spin structure in magnet/heavy metal bilayers. Here, we investigate the SMR in Gd3Fe5O12 (GdIG)/Pt bilayers, where GdIG is a compensated ferrimagnetic insulator. Under a finite magnetic field, GdIG has a collinear magnetic phase far away from compensated temperature (Tcomp) and noncollinear/canted magnetic phase around Tcomp of 278 K. A conventional SMR behavior is observed at different temperatures without any sign change around Tcomp. Meanwhile, an asymmetric behavior (unidirectional-like) exists in the observed SMR at the temperatures just above or below Tcomp, because of the contribution of the anisotropic magnetothermopower effect, i.e., spin Seebeck effect. The spin Seebeck effect component exhibits a sign change around Tcomp, which is correlated with the reversal of the sublattice magnetization. Our finding provides an insight into SMR and thermal spin transport in the GdIG/Pt bilayer structure. [ABSTRACT FROM AUTHOR]

Based on micromagnetic simulations, we show that it is possible to achieve spin–orbit torque field-free switching of a synthetic antiferromagnet comprised of two ferromagnetic layers with perpendicular magnetic anisotropy, sitting on top of a conventional antiferromagnet. Field-free magnetization reversal is propelled by the competing exchange fields and spin torques. Although some antiferromagnetic coupling is necessary to switch both ferromagnetic layers, strong Ruderman-Kittel-Kasuya-Yosida inhibits the switching process due to the strong repelling forces experienced by both FM layers. The switching happens through domain nucleation and propagation and is aided by Dzyaloshinskii–Moriya interactions. The overall heterostructure is applicable in conjunction with a magnetic tunnel junction, where the free layer is comprised of the proposed synthetic antiferromagnet. [ABSTRACT FROM AUTHOR]

A temperature-dependent coherent magnetization reversal model is proposed for size-distributed assemblies of ferromagnetic nanoparticles (NPs). NPs are assumed to be of uniaxial and cubic anisotropies. The thermal dependence is included by considering thermal fluctuations, implemented through the Néel-Arrhenius theory. Theoretically calculated thermal and angular dependences of magnetization reversal loops are obtained. There are similar behaviors for a single NP and an assembly of NPs. In particular, it is shown that the fourfold anisotropy results in double slope loops along the hard axis in both cases. Also, the azimuthal dependence of coercive fields is similar in both cases and with or without the presence of a fourfold anisotropy. There are also important differences in the behaviors observed for a single NP and that of an assembly of NPs. Firstly, the blocking temperature is barely enhanced by the presence of a fourfold anisotropy but is greatly enhanced in the assembly of NPs relative to a single NP. Secondly, along the easy axis, for a single size particle, the shape of the M-H loops is neither temperature dependent nor fourfold anisotropy dependent, as it is always rectangular. However, the shape of the M-H loops for an assembly of NPs is temperature dependent, but this shape is weakly dependent on the anisotropy ratio. Simulations of M-H loops using the model presented here would allow the quantitative determination of the anisotropy constants for either single sized NPs or an assembly with different sizes. [ABSTRACT FROM AUTHOR]

We have reinvestigated the magnetization reversal in perovskites La1–xPrxCrO3, GdCrO3, and TmCrO3 and show that spin rotation or reorientation plays a key role in this property. The magnetization of La1–xPrxCrO3 as well as other chromites, including GdCrO3 and TmCrO3, indicates that the disappearance of magnetization reversal when x is increased from ∼0.85 is caused by a flip of Pr3+ paramagnetic moments antiferromagnetically coupled with canted Cr3+ spins. This is due to a Zeeman energy of Pr3+ in analogy with a spin rotation in GdCrO3 and TmCrO3 below ∼25 K, denoted as the spin reorientation transition. Magnetic susceptibility measurements point to either superparamagnetic or single-molecule-magnet-like glassy behavior in all three systems, which is likely linked to a rotation of the R3+-Cr3+ coupling, as seen from magnetocalorimetry (R = La1–xPrx, Gd, and Tm). We also present a characteristic magnetization switching by rotating the R3+ moments with the aid of large Zeeman energies. [ABSTRACT FROM AUTHOR]

The present work reports the unconventional exchange bias (EB) phenomena in an exchange-coupled hard and soft magnetic bilayer system and the tunability of EB. The EB phenomena, i.e., shifting of the hysteresis loop of the soft (Fe) layer is observed when the hard magnetic ( L 1 0 FePt) layer is under the remanent state indicating the development of unidirectional anisotropy. The nuclear resonant scattering measurements clearly reveal the development of unidirectional anisotropy in the soft magnetic (Fe) layer, when the hard magnetic layer is under the remanent state. The magnetization reversal process is investigated by measuring two in-plane orthogonal components of magnetization, i.e., parallel ( M ∥) and perpendicular ( M ⊥ ) to the applied field using the magneto-optical Kerr effect (MOKE). When the magnetic field is applied parallel (antiparallel) to the biasing field direction, ( H SAT ) magnetization reversal is nonuniform, and on the other hand, the rotation of magnetization is observed when the magnetic field is applied away from the H SAT direction. In addition, the sign inversion of the M ⊥ component is observed when the magnetic field is applied at the same angle on either side of the H SAT direction, which clearly imply the change in handedness of the chirality of spin structure during the magnetization reversal of the soft layer. Further, it is observed that the EB decreases with the increase of soft magnetic (Fe) layer thickness, demonstrating the tunable nature of EB phenomena even in these unconventional systems. [ABSTRACT FROM AUTHOR]

The anomalous Hall effect measurements are used to probe the magnetization reversal of terbium iron garnet (TbIG) thin films at different temperatures. The compensation temperature (Tcomp) of TbIG thin films is revealed, and the film thickness effect on the Tcomp is studied. The results indicate a rise of Tcomp along with decreasing film thickness. We postulate two possible origins for the observed behavior, namely interfacial element diffusion and strain effects between TbIG films and Gd3Ga5O12 substrates. The results have implications for the study of spintronic devices based on ultrathin rare-earth iron garnet thin films. [ABSTRACT FROM AUTHOR]

BiFe0.9Co0.1O3 is a promising material for an ultra-low-power-consumption nonvolatile magnetic memory device because local magnetization reversal is possible through application of an electric field. Here, changes in ferroelectric and ferromagnetic domain structures in a multiferroic BiFe0.9Co0.1O3 thin film induced by "water printing", which is a polarization reversal method involving chemical bonding and charge accumulation at the interface between the liquid and the film, was investigated. Water printing using pure water with pH = 6.2 resulted in an out-of-plane polarization reversal from upward to downward. The in-plane domain structure remained unchanged after the water printing process, indicating that 71° switching was achieved in 88.4% of the observation area. However, magnetization reversal was observed in only 50.1% of the area, indicating a loss of correlation between the ferroelectric and magnetic domains because of the slow polarization reversal due to nucleation growth. [ABSTRACT FROM AUTHOR]

High-entropy perovskite oxide (HEPO) crystallizes in perovskite structure (ABO3) and is characterized by five or more elements sharing one lattice site (A or B). HEPO has received a lot of attention in recent years due to its excellent properties. A single phase (La0.2Y0.2Pr0.2Nd0.2Sm0.2)CrO3 is prepared by solid phase reaction method, and its crystal structure and magnetic properties are investigated here. Although five rare earth elements occupy the same lattice site, a unitary perovskite structure formed. The magnetic measurement results show an antiferromagnetic transition at about 210 K, and interesting magnetization reversal and exchange bias effect at low temperature. [ABSTRACT FROM AUTHOR]

Wiegand wires are unique ferromagnetic materials that display rapid magnetization reversal and a large Barkhausen jump under an applied field. This stable reversal can be used to induce a periodic pulse voltage in a pickup coil wrapped around the Wiegand wire. To unlock the full potential of Wiegand wires for magnetic sensors and devices, the magnetic structure and magnetization state of the Wiegand wire must be fully elucidated. In this study, hysteresis loops were used to reveal the magnetic structure of Wiegand wires. Wiegand wires of different diameters magnetized under different applied magnetic field strengths were analyzed in detail. Our results show that Wiegand wires 0.06 mm in diameter are composed solely of a hard magnetic core. Wiegand wires above 0.10 mm in diameter have a hard magnetic core, a middle layer, and a soft layer that decreases in thickness but increases in coercivity as the wire diameter decreases. Then, theoretical models were built to predict the magnetic structure of Wiegand wires under an applied field for the first time. The magnetization process of Wiegand wires with different diameters under different applied magnetic fields was also analyzed. [ABSTRACT FROM AUTHOR]

High-entropy perovskite oxide (HEPO) crystallizes in perovskite structure (ABO3) and is characterized by five or more elements sharing one lattice site (A or B). HEPO has received a lot of attention in recent years due to its excellent properties. A single phase (La0.2Y0.2Pr0.2Nd0.2Sm0.2)CrO3 is prepared by solid phase reaction method, and its crystal structure and magnetic properties are investigated here. Although five rare earth elements occupy the same lattice site, a unitary perovskite structure formed. The magnetic measurement results show an antiferromagnetic transition at about 210 K, and interesting magnetization reversal and exchange bias effect at low temperature. [ABSTRACT FROM AUTHOR]

Magnetic hysteresis and coercivity mechanism of a permanent magnet have been long discussed, and their understandings have been significantly deepened during the last decade. Magnetization reversal in a permanent magnet proceeds with thermally activated nucleation and domain wall depinning processes followed by magnetic domain expansions. To treat theoretically the thermally activated magnetization reversal process, atomistic spin model and continuum calculations have been performed. Through these multi-scale calculations, the physical meanings of fluctuation field and activation volume which have been used phenomenologically become very clear. Experimental approaches for both microscopic and macroscopic thermally activated magnetization reversal processes and magnetic domain growths have been also performed. It is expected that these theoretical and experimental multi-scale studies will be integrated to fully understand the magnetic hysteresis and coercivity mechanism with the aid of data science technologies in the future. [ABSTRACT FROM AUTHOR]

Electrodynamic, quasi-static magnetic hysteresis loops and the form of the domain texture of a single-crystal plate have been experimentally obtained. Using mathematical modeling, the change in the dynamic magnetic hysteresis (the magnetic loss energy per unit volume per magnetization reversal cycle) depending on the frequency of the magnetic field is shown. This dependence is due to the inertia of the magnetization of the sample. With a change in frequency, the dynamic magnetic hysteresis can differ significantly from the hysteresis in the case of quasi-static magnetization reversal. [ABSTRACT FROM AUTHOR]

A theoretical and experimental study of the dependence of the magnetoresistance for two spin-tunnel junctions (STJs) of ellipsoidal shape has been made. The one-sided homogeneous magnetization reversal mode of an ellipsoidal STJ with different aspect ratios has been experimentally selected. Despite the reverse inhomogeneous remagnetization, this selection has allowed for the calculation of the magnetic parameters of these elements by developing the Stoner-Wohlfarth theory. [ABSTRACT FROM AUTHOR]

Realization of a magnetization reversal by an external electric field is vital for developing ultra-low-power spintronic devices. In this report, starting from energy band engineering, a general design principle is proposed for achieving electrical manipulation of a nonvolatile 180° magnetization reversal. A half semiconductor (HSC) and a bipolar magnetic semiconductor (BMS) are selected as the model of magnetic layers, whose conduction-band minimum and valence-band maximum are in the same and opposite spin states, respectively. Based on the analysis of virtual hopping and tight-binding models, the interlayer coupling of HSC/insulator/BMS devices is successfully tuned between ferromagnetic and antiferromagnetic interactions by varying electric field directions. Moreover, the interlayer coupling nearly disappears after removing the electric field, proving the nonvolatile magnetization reversal. Using first-principles calculations, the feasibility of present design strategy is further confirmed by a representative device with the structure of CrBr3/h-BN/2H-VSe2. This design guideline and physical phenomena may open an avenue to explore magnetoelectric coupling mechanisms and develop next-generation spintronic devices. [ABSTRACT FROM AUTHOR]

Magnetic materials play a vital role in energy-efficient data storage technologies, combining very fast switching with long-term retention of information. However, it has been shown that, at very short time scales, magnetisation dynamics become chaotic due to internal instabilities, resulting in incoherent spin-wave excitations that ultimately destroy magnetic ordering. Here, contrary to expectations, we show that such chaos gives rise to a periodic pattern of reversed magnetic domains, with a feature size far smaller than the spatial extent of the excitation. We explain this pattern as a result of phase-synchronisation of magnon-polaron quasiparticles, driven by strong coupling of magnetic and elastic modes. Our results reveal not only the peculiar formation and evolution of magnon-polarons at short time-scales, but also present an alternative mechanism of magnetisation reversal driven by coherent packets of short-wavelength magnetoelastic waves. Increasing the speed of magnetization switching is an obvious pathway to improve spintronic device performance. However, very fast magnetization switching is accompanied by instabilities. Here, Gidding et al study these instabilities using optical pumping, and show that instability generated spin-waves can achieve a high enough amplitude to drive switching of the magnetization, with a distinctive coherent pattern. [ABSTRACT FROM AUTHOR]

The robustness of spin–orbit torque (SOT) induced magnetization switching and ease of deposition make type-X devices, where the in-plane easy axis lies perpendicular to the spin polarization, attractive in the field of spintronics. However, universally applicable and straightforward detection of type-X magnetization reversal is still elusive, unlike type-Z switching, which employs DC-based anomalous Hall effect measurement. Here, we demonstrated that the odd planar Hall voltage (O-PHV) signal exhibits an odd symmetry with the application of an external magnetic field which motivates us to develop a reading mechanism for detecting magnetization switching of in-plane magnetized type-X devices. We verified our DC-based reading mechanism in the Pt/Co/NiFe/Pt stack where a thin Co layer is inserted to create dissimilar interfaces about the NiFe layer. Remarkably, the current-induced in-plane fields are found to be significantly large in Pt/Co/NiFe/Pt stack. Furthermore, we employed the O-PHV method to detect the current-induced magnetization switching. The pure DC nature of the writing and reading mechanism of our proposed type-X detection technique through O-PHV makes it the easiest in-plane magnetization detection technique. Moreover, the high repeatability and easy detection of our proposed method will open avenues toward in-plane SOT switching based memory devices and sensors. [ABSTRACT FROM AUTHOR]

Fe-Co–Ni magnetic nanowire arrays (MNWs) with three-dimensional periodic structures were successfully prepared by direct current (DC) Electrodeposition. XRD results show that Fe-Co–Ni MNWs have a strong preferred orientation in the direction of the body-centered cubic structure (bcc) FeCo (110). The VSM results demonstrate that the coercivity of Fe-Co–Ni MNWs is relatively low, indicating the soft magnetic properties of Fe-Co–Ni MNWs. Further investigation of its magnetization reversal mechanism reveals the combination of curling rotation and coherent rotation. The Fe-Co–Ni MNWs with three-dimensional periodic structures prepared in this paper have potential applications in sensing and spintronic fields. [ABSTRACT FROM AUTHOR]

In this paper, our objective was to investigate the static and dynamic magnetic properties of Fe3O4 nanotubes that are 1000 nm long, by varying the external radius and the thickness of the tube wall. We performed a detailed numerical analysis by simulating hysteresis curves with an external magnetic field applied parallel to the axis of the tubes (along the z-axis). Our findings indicate that nanotubes with an external radius of 30 nm exhibit non-monotonic behavior in their coercivity due to a change in the magnetization reversal mechanism, which was not observed in nanotubes with external radii of 80 nm. Additionally, we explored the dynamic susceptibility of these nanotubes and found that the position and number of resonance peaks can be controlled by manipulating the nanotube geometry. Overall, our study provides valuable insights into the behavior of Fe3O4 nanotubes, which can aid in the design and improvement in pseudo-one-dimensional technological devices. [ABSTRACT FROM AUTHOR]

• Micromagnetic study of nanosphere lithography-inspired nanostructure. • Hysteresis loops are analysed with varying thickness. • Thinner structure reverses in-plane while thicker one switches out-of-plane. • Spin textures are linked to energy variation and spin canting angle. • The results lay the groundwork for future research on artificial magnetic lattices. Artificially fabricated magnetic lattices, especially those created via nanosphere lithography, have garnered significant research interest due to their unique properties and potential applications across various technologies. This article examines micromagnetic simulation studies of a conventional nanosphere lithographed thin-film structure, which can be created through normal incidence shadow mask deposition, considering cobalt (Co) as the constituent material. Simulations are conducted on a hexagonally symmetric lattice with curved triangular elements mimicking the lithographed structure to analyze hysteresis loops at varying thicknesses in the range between 4 nm to 8 nm. We examine the spin textures during magnetization reversal and the variation in energies during the reversal process. Interestingly, our findings indicate that the variation in the system's total energy as a function of nanostructure thickness is qualitatively driven by changes in Zeeman energy likely linked to the spin canting angle. The findings provide a valuable foundation for advancing research on artificial magnetic lattices using nanosphere lithography. [ABSTRACT FROM AUTHOR]

• We propose an innovative method to manipulate magnetization reversal sequences by altering the magnetic field direction. • The FORC analysis method provides a comprehensive insight into the reversal mechanism in synthetic antiferromagnets. In this study, a synthetic antiferromagnet (SAF) composed of [Co/Ni]/Ir/[Ni/Co] with perpendicular magnetic anisotropy (PMA) was fabricated using magnetron sputtering. The magnetization reversal observed in synthetic antiferromagnets is typically attributed to the competition among Zeeman, anisotropy, and exchange coupling energies. Once fabricated, the reversal sequences of the two ferromagnetic layers within this structure remain consistent. This study introduces an innovative method for manipulating magnetization reversal sequences by adjusting the direction of the magnetic field. First order reversal curves (FORC) can be utilized to analyse the magnetic reversal behaviors of synthetic antiferromagnets by varying the direction of the external magnetic field. [ABSTRACT FROM AUTHOR]

• Magnetooptics in transmission applied to vector magnetometry of synthetic antiferromagnets. • Magnetooptic reading of binary information in synthetic antiferromagnets. • The approach can be extended to more complicated magnetization configurations with the zero magnetic moments. The potential of the transmission magnetooptics for the studies of magnetization profiles in synthetically layered antiferromagnetic nanostructures (synthetic antiferromagnets) is evaluated. The systematic evaluation is performed on a model structure formed by two iron layers of the varying thickness, d , in the nanometer range, separated from each other by a gold spacer 1 nm thick on a gold 30 nm thick substrate, Fe↑(d nm)/Au(1 nm)/Fe↓(d nm)/Au(30 nm). Despite the vanishing total magnetization, the magnetooptic (MO) response is nonzero. The d dependence of MO response displays maxima followed by saturation with increasing d. A simultaneous reversal of magnetization in the iron layers produces the sign reversal of the MO response. [ABSTRACT FROM AUTHOR]

This study investigates the static and dynamic magnetic properties of helically shaped permalloy nanowires through micromagnetic simulations. We performed comprehensive numerical analyses to simulate hysteresis curves under an externally applied magnetic field aligned along the z-axis, focusing on the impact of the helicoidal geometry on the magnetic reversal mechanism. Our results reveal that, under specific geometric conditions, magnetization reverses through three distinct mechanisms. In Region I, vortex-type domain walls with varying chirality propagate at the top and bottom of the nanowire. In Region II, these walls exhibit uniform chirality at both ends, while in Region III, vertical vortices dominate. Additionally, we examined the dynamic susceptibility of the nanowires in the frequency range of 0–20 GHz. We found that varying the degree of helicoidal geometry influences both the position and the number of resonance peaks. Beyond these fundamental insights, our study highlights the potential applications of helically shaped nanowires in advanced magnetic sensing, data storage, and nanoscale spintronic devices. [Display omitted] • Comprehensive micromagnetic simulations of helically shaped permalloy nanowires. • Three distinct magnetization reversal mechanisms identified based on geometry. • Geometrical modifications influence dynamic susceptibility and resonance modes. • Potential applications in magnetic sensing, data storage, and spintronic devices. • Insights into nanoscale devices, such as magnonic filters, via geometric changes. [ABSTRACT FROM AUTHOR]

Developing high-performance nanocrystalline SmCo permanent magnets is essential for high-temperature applications in advanced electromechanical equipment. In this study, the nanocrystalline anisotropic Sm 0.4 Pr 0.6 Co 5 magnets with controllable magnetic properties were achieved by adjusting the deformation temperature. The Sm 0.4 Pr 0.6 Co 5 magnet deformed at 780 ℃ showed a high coercivity of 19.7 kOe (1.57 MA/m) at 300 K and of 9.3 kOe (0.739 MA/m) at 573 K, resulting in the temperature coefficient of −0.189 %/℃. The magnet deformed at 840 ℃ exhibited a strong c-axis texture and the maximum magnetic energy product of 22.3 MGOe (177 kJ/m3). The hot-deformed Sm 0.4 Pr 0.6 Co 5 magnets showed the microstructure with coexisting RECo 5 main phase grains and dispersible RE-rich phase nanoprecipitates. As the temperature increased, the crystallographic orientation, grain size and magnetic domain size were increased. The coercivity mechanism of hot-deformed Sm 0.4 Pr 0.6 Co 5 magnets was controlled by nucleation, and the high deformation temperature led to a decrease in the reverse nucleation field and coercivity, accompanied by a large reversible magnetization during magnetization reversal and a large recoil magnetic permeability. This study provides valuable insights into optimizing the microstructure and magnetic properties of nanocrystalline SmCo 5 magnets, which is expected to promote high temperature applications of rare earth permanent magnet materials. • Anisotropic nanocrystalline Sm 0.4 Pr 0.6 Co 5 magnets with tunable magnetic properties and microstructure were achieved. • The H ci temperature-coefficient β 300K-573K of -0.189 %/℃ and (BH) max of 22.3 MGOe can be obtained. • Coercivity mechanism of anisotropic nanocrystalline Sm 0.4 Pr 0.6 Co 5 magnets was controlled by nucleation. [ABSTRACT FROM AUTHOR]

The magnetic feature of a faceted double perovskite Nd 2 FeCrO 6, synthesized by the solid-state reaction method, is investigated. Nd 2 FeCrO 6 exhibits an orthorhombic structure with Fe and Cr ions in 3+ oxidation states. These ions are shifted away from the centre of FeO 6 /CrO 6 octahedral sublattice, indicating distortion. The Isomer shift in the Mössbauer spectrum correlates with the 3+ oxidation state of Fe, and the existence of magnetic fraction leading to magnetic frustration in Nd 2 FeCrO 6 is established. The superexchange Fe3+ -O- Fe3+ and Cr3+ -O- Cr3+ interactions favour antiferromagnetic ordering, while Fe3+ -O- Cr3+ interactions promote weak ferromagnetic ordering. The low-temperature magnetic study traces negative magnetization in FC mode for the applied external fields of 100 Oe and 1000 Oe, attributed to the paramagnetic effect of Nd3+ ions aligning antiparallel to the ferromagnetic component of the |Fe+Cr| sublattice internal field. Also, the negative magnetization of FC mode is found to be field-dependent. The deviation of the B 2 g phonon around the magnetic ordering temperature T N ∼250 K provides evidence of spin-phonon coupling. This variation in the B 2 g phonon is analysed in terms of the full width at half maximum (FWHM), peak position, intensity, and height. • Double perovskite Nd 2 FeCrO 6 (NFCO) synthesized by the solid-state reaction method, is investigated. • The low-temperature magnetic study traces negative magnetization in FC mode for the applied external fields of 100 Oe and 1000 Oe, attributed to the paramagnetic effect of Nd3+ ions aligning antiparallel to the ferromagnetic component of the |Fe+Cr| sublattice internal field. Also, the negative magnetization of FC mode is found to be field-dependent. • NFCO shows a deviation in the observed B 2 g phonon mode peak position before and after T N ∼ 250 K, confirming the presence of spin-phonon coupling. • LTHM- 57Fe Mössbauer spectrum collected at 300 K shows one magnetic sextet and a 6-line magnetic splitting at 5 K and 5 K with 5 T. [ABSTRACT FROM AUTHOR]

In this study, tunable bipolar magnetization reversal with an inverse exchange bias effect and magnetically switched magnetocaloric effect are reported in the hetero-tri-spin of a 3 d -5 d -4 f based Gd 2 NiIrO 6 (GNIO) polycrystalline sample. The sample was prepared using a conventional solid-state reaction method. Temperature (T)-dependent direct current (DC) and alternating current (AC) magnetic susceptibility studies revealed that GNIO exhibits ferrimagnetic (FiM) behavior below the transition temperature T N ∼164 K owing to the Ni2+– O2-– Ir4+ superexchange interactions. With the application of 500 Oe, low-field-cooled (H FC) induced magnetization reversal (MR) below the compensation temperature (T comp) ∼28 K, and a spin re-orientation (SR) like behavior at T SR ∼96 K were observed in FC mode within the temperature region of T comp < T SR < T N. T he observed negative magnetization across the magnetic compensation could be attributed to the competing magnetic interactions arising from the thermal variations in the magnetic moments of the Gd and Ni-Ir sublattices. An inverse exchange bias effect was observed from isothermal magnetization measurements, where the M (H) loop shifted after field-cooling (H FC). The H -assisted magnetization switching confirmed the spin reversal phenomenon, and temperature-dependent magnetic entropy changes complemented both the conventional and inverse magnetocaloric effects. Density functional theory (DFT) calculations employing the generalized gradient approximation (GGA) and the Hubbard U model along with spin-orbit coupling confirmed that the FiM phase is the most stable magnetic state for GNIO. This finding is in good agreement with the experimental observations. Interestingly, the calculated spin-polarized density of states revealed a dominant contribution of Ir d over Ni d near the Fermi level, confirming the Mott-insulating behavior of GNIO. • Complex magnetic behaviour in hetero-tri-spin of 3 d -5 d -4 f based Gd 2 NiIrO 6 polycrystals. • Multiple magnetic transitions: ferrimagnetic at 164 K, compensation temperature at 28 K, and spin re-orientation at ∼ 96 K. • Magnetization switching from conventional to inverse magnetocaloric effect. • DFT calculations using GGA+ U +SOC approach predicts the monoclinic structure with ferrimagnetic semiconductor behavior. • Calculated spin-polarized density of states suggests the Mott-insulating behavior of Gd 2 NiIrO 6 [ABSTRACT FROM AUTHOR]

The coercivity mechanism and magnetization reversal process of anisotropic La-Nd-Dy-Fe-B micron-sized films have been investigated. By varying the thickness of the single-layer film from 500 nm to 6 μm, the highest coercivity of 1.88 T in the film with 3 μm thickness is achieved at 300 K, due to the large dipole interaction and domain pinning effect. When the thickness is further increased to 6 μm, the coercivity decreases sharply to 1.11 T due to the microstructure and phase formation in the film. In the 6 μm multilayer film, the addition of a Ta spacer layer further enhances perpendicular magnetic anisotropy, the dipole interaction, and adjusts the phase distribution, collectively boosting the coercivity of the micron-sized film (1.63 T). As thickness of the film increases, the dominant mechanism of coercivity shifts from a pinning mechanism to a nucleation mechanism. This study contributes to the understanding of the coercivity mechanism and magnetization reversal process in La-Nd-Dy-Fe-B permanent magnet micron-sized films. [ABSTRACT FROM AUTHOR]

The unique physicochemical properties of metallic and magnetic nanowires, whether obtained in well-ordered arrays or as single, isolated, and free-standing structures from patterned templates, have been extensively studied for various technological applications. These applications include magnetic data storage, sensing, biolabeling, barcoding, among many others. Novel template-assisted methods for the synthesis of metallic nanowires offer an enhancement over the control of their shape and morphology, compositional uniformity, and interconnectivity, allowing them for being applied as new metamaterials for novel multifunctional applications. Within this critical review, an extensive overview focused on the synthesis and characterization of the particular properties exhibited by multilayered and multisegmented metallic nanowires having specifically controlled geometries and compositional graded designs through employing electrochemical techniques based on sacrificial nanoporous alumina template-assisted methods, is presented. We review recent advancements in designing synthesis protocols for fabricating new metallic nanowires with multifunctional applications. These protocols offer competitive fabrication costs compared to conventional laboratory procedures, potentially expanding their use in various research areas. In this review, we also establish the new challenges and suggest the future perspectives and expectations that will be covered by these new metamaterial-based nanowires.

We studied the magnetic properties of a glass-covered amorphous microwire that was stress-annealed at temperatures distributed along the microwire length. The Sixtus-Tonks, Kerr effect microscopy and magnetic impedance techniques have been applied. There was a transformation of the magnetic structure across the zones subjected to annealing at different temperatures. The annealing temperature distribution induces the graded magnetic anisotropy in the studied sample. The variety of the surface domain structures depending on the longitudinal location has been discovered. Spiral, circular, curved, elliptic and longitudinal domain structures coexist and replace each other in the process of magnetization reversal. The analysis of the obtained results was carried out based on the calculations of the magnetic structure, assuming the distribution of internal stresses. [ABSTRACT FROM AUTHOR]

Amorphous microwires have attracted substantial attention in the past decade because of their useful technological applications. Their bistable magnetic response is determined by positive or negative magnetostriction, respectively. First-order reversal curves (FORC) are a powerful tool for analyzing the magnetization reversal processes of many-body ferromagnetic systems that are essential for a deeper understanding of those applications. After theoretical considerations about magnetostatic interactions among microwires, this work introduces a systematic experimental study and analysis of the FORC diagrams for magnetostrictive microwires exhibiting an individually bistable hysteresis loop, from a single microwire to sets of an increasing number of coupled microwires, the latter considered as an intermediate case to the standard many-body problem. We performed the study for sets of quasi-identical and different hysteretic microwires where we obtained the coercivity H c and interaction H u fields. In the cases with relevant magnetostatic interactions, FORC analysis supplies deeper information than standard hysteresis loops since the intrinsic fluctuations of the switching field generate a complex response. For sets of microwires with very different coercivity, the coercivity distributions of the individual microwires characterize the FORC diagram. [ABSTRACT FROM AUTHOR]

An investigation is conducted for the coercivity mechanism in as‐spun Pr2Fe14B/α‐Fe ribbons containing different phosphorus (P) prepared at a wheel speed of 30 ms−1. With the increase of P addition, the volume of the amorphous phase in the ribbons is increased, and the grain size of Pr2Fe14B is decreased. The hysteresis loops of the ribbons with 0.1 at% P exhibit a homogeneous magnetization reversal process similar to single‐phase magnet, demonstrating that soft magnetic grains are fully coupled with the hard ones. The highest coercivity of 12.0 kOe (300 K)–38.0 kOe (100 K) is achieved in the ribbon with 0.3 at% P‐addition, which shows weak exchange coupling interaction between grains, and the high coercivity comes mainly from the decoupled hard phase. The values of the microstructure parameter αkαex in all compositions are less than 0.3 and imply that the main coercivity mechanism is the mixture of the nucleation of reverse domain and domain wall pinning. The minor hysteresis loops and initial magnetization curves show the dominant domain wall pinning in the ribbon with 0–0.1 at% P, nucleation and pinning in the ribbon with 0.3 at% P, and dominant domain nucleation in the ribbon with 0.5 at% P. [ABSTRACT FROM AUTHOR]

In this paper, we demonstrate that V0.027Bi0.973TeI, a material with both giant bulk Rashba effect and ferromagnetism, can reverse its magnetization by self-generated spin–orbit torque. Through first-principles calculation, it is found that the giant bulk Rashba effect arises from both bulk space inversion asymmetry and strong spin–orbital coupling, while the ferromagnetism originates from the itinerant d-electrons of doped element vanadium. More importantly, its field-like spin–orbit torque efficiency is determined to be as high as 4.53 × 10−4 mT/(A cm−2), which is more than two orders of magnitude higher than that typically observed in magnetic heterostructures. It is further shown that by using such magnetic bulk Rashba material to form a homogenous spintronic device, the power consumption for magnetization switching can be significantly reduced. [ABSTRACT FROM AUTHOR]

In this report, we studied the dependence of output voltage on the damping constant, the frequency of the pulse current, and the wire length of zero-magnetostriction CoFeBSi wires using multiphysics simulation considering eddy currents in micromagnetic simulations. The magnetization reversal mechanism in the wires was also investigated. As a result, we found that a high output voltage can be achieved with a damping constant of ≥0.03. We also found that the output voltage increases up to a pulse current of 3 GHz. The longer the wire length, the lower the external magnetic field at which the output voltage peaks. This is because the demagnetization field from the axial ends of the wire is weaker as the wire length is longer. [ABSTRACT FROM AUTHOR]

Starting from the magnetic Langevin equation and its associated Fokker–Planck equation, governing the reversal magnetization of single-domain ferromagnetic nanoparticles elucidated by Brown's model [W. F. Brown, Phys. Rev. 130 (1963) 1677; IEEE Trans. Mag. 15 (1979) 1196], the magnetic hysteresis loops and the specific absorption rate of nanoparticles with biaxial anisotropy are investigated. An illustration of the effect of the temperature and the applied magnetic field across a wide range of frequencies on both of the former quantities is revealed. Emerged new physical insights elucidated from the present study hold promise for realistic nanoscale medicinal applications and may pave the way for an accurate notable benefit of superparamagnetic nanoparticles having biaxial anisotropy in oncology. [ABSTRACT FROM AUTHOR]

This paper presents the structural and magnetic properties of polyvinyl alcohol/iron (PVA/Fe) nanocomposite films. Iron (Fe) films of different thicknesses were deposited on a PVA substrate using ion beam sputtering. The Fe nanoparticle layer thickness ranges from 3 to 50 nm on the PVA substrate. Grazing incidence x-ray diffraction has been carried out to study the structural behavior of the prepared films. An atomic force microscope records the indicated remarkable change in the roughness of the nanocomposite film as a result of initiation of vertical growth of sputtered Fe nanoparticles.Magneto-optic Kerr effect (MOKE) magnetometry and MOKE spectroscopy have been employed to evaluate the magnetic property and simultaneously study the real time growth of the magnetic domain structure for both 0° and 90° azimuthal angles. MOKE microscopic images indicated the magnetization reversal commensurate with the hysteresis loop of the nanocomposites. All the films show soft ferromagnetic behavior. Gradual development of the domain structure is observed in the MOKE micrograph with the increase in the thickness of Fe nanoparticle deposition. Ex situ magnetic force micrographs of the magnetic domain structures supported the observation of MOKE microscopic studies, which indicated switching of in-plane magnetization to out-of-plane magnetization near an Fe nanoparticle deposition thickness of 40 nm. The PVA matrix appears to be an effective material to support the growth of magnetic properties in the PVA/Fe nanocomposite system. The evolution of Fe nanostructures on PVA and the resulting magnetic behavior have been discussed. [ABSTRACT FROM AUTHOR]