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With significant recent progress in the thin film deposition and nanofabrication technology, a number of physical phenomena occur at the interfaces of magnetic thin films, and their heterostructures have been discovered. Consequently, the electric field-induced modulation of those interfacial properties mediated through spin–orbit coupling promises to develop magnetic material based smarter, faster, miniaturized, energy efficient spintronic devices. Among them, the electric field-induced modification of interfacial magnetic anisotropy, popularly termed as voltage-controlled magnetic anisotropy (VCMA), has attracted special attention because of its salient features. This article is devoted to reviewing the recent development of magnonics, which deals with collective precessional motion of ordered magnetic spins, i.e., spin waves (SWs), and skyrmions with chiral spin textures, with VCMA, including the perspectives of this research field. Starting with a broad introduction, the key features of VCMA and its advantages over other electric field-induced methods are highlighted. These are followed by describing the state-of-the-art of VCMA, and various other direct and indirect electric field-induced methods for magnetization reversal; controlling skyrmion dynamics; excitation, manipulation, and channeling of SWs; and tailoring magnonic bands. The critical challenges, their possible solutions, and future perspectives of this field are thoroughly discussed throughout the article. [ABSTRACT FROM AUTHOR]

It is crucial to better understand the magnetization reversal process between soft and hard magnets and to achieve a high maximum energy product in thick composite multilayers. In this study, we find that the exchange interactions dominate in soft–hard-magnetic composite bilayers, while dipole interactions are predominant in soft–hard-magnetic composite trilayers. Based on the first-order reversal curve, magnetization reversal models are developed for both the thick composite bilayer and trilayer. Dipole interactions play an important role in the long range, resulting in higher coercivity and remanence in the thick trilayer. A multilayer in a stacked trilayer structure is achieved, which is composed of thick films with a perpendicular magnetic anisotropy at a thickness of up to 16 μm. The enhanced dipole interactions lead to a remanent polarization of 1 T and a maximum energy product of 22.5 MGOe. This work contributes to the preparation of thick films with a high maximum energy product for applications in magnetic microelectromechanical systems. [ABSTRACT FROM AUTHOR]

Writing and reading of magnetization states via mechanical strain are crucial for the development of ultralow-power spintronic devices. In this study, a van der Waals magnetic tunnel junction (vdW MTJ) of Fe3GaTe2/h-BN/MnBi2Te4 is constructed to explore the magnetization reversal under in-plane biaxial strains. Interestingly, the interlayer magnetic coupling of devices can be tuned to ferromagnetic and antiferromagnetic states by tensile and compressive strains, respectively. The various magnetic couplings on applied strains are analyzed using the superexchange theory. Importantly, the interlayer coupling nearly vanishes after removing external strains, ensuring the nonvolatility of magnetization reversal, resulting in the nonvolatile writing of magnetization states in the present vdW MTJ. Moreover, the tunneling magnetoresistance ratio of the device is up to −5745%, which remains −1478% even with −2% strain, showing great potential for reading the magnetization states. Therefore, this work provides an alternate avenue to write and read magnetization states in one vdW MTJ under biaxial strains. [ABSTRACT FROM AUTHOR]

We have investigated the magnetization reversal processes and dynamic behavior of trilayered Py(50 nm)/Pd(tPd)/Py(20 nm) nanowires with periodic width modulation as a function of spacer layer thickness tPd in the range from 0 to 10 nm and compared them with single-layer nanowires. The ferromagnetic resonance spectra show more than three modes that result from a non-uniform demagnetizing field in width-modulated nanowires. We observe that the spacer layer thickness influenced the ferromagnetic resonance spectra, which showed different numbers and values of modes and frequencies due to the different magnetization configurations for different spacer layer thicknesses. We also found that the two ferromagnetic layers are exchange-coupled for tPd = 2 nm nanowire arrays, showing the sharp switching of magnetization from the static measurements and sharp frequency jump from 13.6 to 14.7 GHz around −18 mT from the dynamic measurements. However, for tPd = 10 nm, the two layers switch at different fields, indicating a gradual decrease in magnetization as the reversal is mediated through dipolar coupling. The origin of modes is well explained from the spatial mode profiles of top and bottom magnetic layers. The dynamic responses in this spin-valve-type structure are useful for designing microwave-based spintronic devices. [ABSTRACT FROM AUTHOR]

Pointed magnetic elements are introduced as an improvement upon rectangular strips currently employed in composite element magnetic barcodes. The coercivity of these elements, as measured using the magneto-optic Kerr effect, is found to strictly adhere to a single power law relationship with the element width, where the power law exponent is dependent on the length of the pointed region and takes values between − 0.98 and − 0.91. The steeper gradients here, along with the absence of the crossover region seen in rectangular devices, present these structures as a strict improvement in terms of potential device applications. These improvements are found to be present for all structures where the pointed region is as long as, or longer than, the magnetic element is wide. The remanent magnetization configuration, imaged using photo-emission microscopy with contrast from x-ray magnetic circular dichroism (XMCD-PEEM), is compared to the results of micromagnetic simulations. It is found to cant inward in the pointed section of the strip, aligning with the edges of the point, pinning the magnetization and giving a consistent magnetization reversal behavior for all element widths investigated. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Many sandwich‐type lanthanide complexes show extremely high energy barriers (Ueff) for the reversal of magnetization and high blocking temperatures, being the star molecules in the research area of single‐molecule magnets. Herein, the preparation, structural determination, and magnetic property studies of two ansa‐bridged Er‐COT (COT = cyclooctatetraenyl dianion) complexes [KDME2][Er((η8‐COT‐SiMe2)2O)] (1) and [KDME2][Er((η8‐COT‐SiiPr2)2O)]K[Er((η8‐COT‐SiiPr2)2O)] (2) were reported. The Er(III) ions in both complexes are sandwiched by two COT rings which are ansa‐bridged by a [Si‐O‐Si] group. Magnetic studies reveal both complexes display slow magnetic relaxations with comparable energy barriers (228(5) K for 1, and 196(4) K for 2) and blocking temperatures (10.5 K for both complexes). The difference in the relaxation times (τ) for the two complexes was studied in details: different molecular vibrations induced by the substituents are the main reason for τ for 1 being about 10 times longer than for 2 at the same temperature above 10 K, while the quantum tunnelling of magnetization relaxation time (τQTM) for 2 is about 10 times longer than for 1 below 8 K, probably owing to the different dipolar interactions. Further rearrangement of molecular network with such ansa‐bridged SMMs is promising to design molecular magnetic materials with enhanced properties or new properties. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Many sandwich‐type lanthanide complexes show extremely high energy barriers (Ueff) for the reversal of magnetization and high blocking temperatures, being the star molecules in the research area of single‐molecule magnets. Herein, the preparation, structural determination, and magnetic property studies of two ansa‐bridged Er‐COT (COT = cyclooctatetraenyl dianion) complexes [KDME2][Er((η8‐COT‐SiMe2)2O)] (1) and [KDME2][Er((η8‐COT‐SiiPr2)2O)]K[Er((η8‐COT‐SiiPr2)2O)] (2) were reported. The Er(III) ions in both complexes are sandwiched by two COT rings which are ansa‐bridged by a [Si‐O‐Si] group. Magnetic studies reveal both complexes display slow magnetic relaxations with comparable energy barriers (228(5) K for 1, and 196(4) K for 2) and blocking temperatures (10.5 K for both complexes). The difference in the relaxation times (τ) for the two complexes was studied in details: different molecular vibrations induced by the substituents are the main reason for τ for 1 being about 10 times longer than for 2 at the same temperature above 10 K, while the quantum tunnelling of magnetization relaxation time (τQTM) for 2 is about 10 times longer than for 1 below 8 K, probably owing to the different dipolar interactions. Further rearrangement of molecular network with such ansa‐bridged SMMs is promising to design molecular magnetic materials with enhanced properties or new properties. [ABSTRACT FROM AUTHOR]

The search for spin-reorientation (SR) phase transitions, a spontaneous rotation of ordered magnetic moments, in ferrimagnetic (FiM) materials, which carry a net magnetization, is of fundamental and practical interest for applications in the field of spintronics. In this work, we have investigated Mn self-doped (Er 0.7 Mn 0.3)MnO 3 solid solution with GdFeO 3 -type Pnma perovskite structure by combining specific heat, magnetic susceptibility and neutron powder diffraction measurements. We provide experimental evidence for FiM order below T C = 104 K, and a spontaneous SR transition at T SR = 11 K. A FiM structure appears in all (R 1-x Mn x)MnO 3 compounds with R = Dy–Lu for x ≥ 0.2. But in this structural family, R = Er is the only material with a SR transition. FiM order in (Er 0.7 Mn 0.3)MnO 3 appears with ferromagnetic (FM) ordering of Mn3+ and Mn4+ cations at the B site along the a -direction, which are antiferromagnetically (AFM) coupled with Er3+ and Mn2+ cations at the A site. At T SR , ordered Er3+ change direction from the magnetically harder a -axis to the magnetically easy b -axis and induce a change of the whole FiM structure, including the direction of all Mn spins from the irreducible representation m GM3+ to m GM4+. We calculated the crystal-field (CF) anisotropy for Ho3+ in (Ho 0.8 Mn 0.2)MnO 3 and Er3+ in (Er 0.7 Mn 0.3)MnO 3 , based on the point charge model; the results revealed large magnetic anisotropies. For the FiM structure of (Ho 0.8 Mn 0.2)MnO 3 , the magnetically easy a -axis of Ho3+ keeps the high-temperature magnetic directions along the a -axis and gives rise to a pronounced magnetization reversal effect at low temperature because of a significant rise of Ho3+ ordered moments. On the other hand, for the FiM structure of (Er 0.7 Mn 0.3)MnO 3 , the magnetically easy b -axis of Er3+ gives rise to a SR phase transition at T SR , which does not lead to magnetization reversal even though Er3+ ordered moments rise significantly at low temperatures. [ABSTRACT FROM AUTHOR]

(100- x) Sr0.7La0.3Fe11.75Co0.25O19–(x) CoFe2O4 composites were synthesized by the one pot sol–gel auto-combustion method. The individual phase purity, morphology, and magnetic hysteresis loop of the composite magnet were analyzed by x-ray powder diffraction, field emission scanning electron microscopy and vibrating sample magnetometer, respectively. The apparent observation of the room temperature hysteresis loop indicates the existence of interfacial exchange interactions. Nevertheless, saturation magnetization (Ms) follows the trend of Vegard's law. The nature of magnetic interaction and its dependency on the amount of each phase were analyzed by employing the Thamm–Hesse plot. The critical size of the soft phase particle did not corroborate with the results of Δ M v s H plot. However, this synthesis method is found to be successful in obtaining single-step magnetization reversal in hard–soft composite magnets. The deviation from ideal non-interacting Stoner–Wohlfarth particles puts the single hard phase into the limelight. The (BH)max in the range of 1.07–0.98 MGOe has been obtained for the synthesized composite magnet. [ABSTRACT FROM AUTHOR]

Ultrafast thermally induced magnetization switching (TIMS) with femtosecond lasers has attracted much attention due to its ability to trigger a single switching on the picosecond time scale. Currently, most of the studies on TIMS have focused on various ferrimagnetic alloys. In this paper, TIMS of Gd/Fe multilayers in different monolayer ratios is investigated by atomic spin dynamics. The results show that an increase in the monolayer Gd ratio narrows the energy density window of the switching. Further studies found that a lower damping ratio decreases the laser energy density threshold for magnetization reversal. Moreover, reducing the ratio of Gd in the monolayer at the appropriate energy density can shorten the duration of the transient ferromagnetic-like state, which can lead to faster realization of TIMS. Our simulation results provide new insights to explore the physical mechanism of TIMS in Gd/Fe multilayers. [ABSTRACT FROM AUTHOR]

All‐optical magnetization reversal provides a low‐power approach for investigating spin state manipulation in 2D magnets. However, the ambient observation of photomagnetic coupling presents significant challenges due to the low Curie temperatures exhibited by most 2D magnets. Herein, a mixed‐dimensional heterostructure comprising a surface‐oxidized Fe3GeTe2 nanosheet with enhanced magnetic properties and individual semiconducting ZnO nanorod is proposed to explore proximity photomagnetic modulation and spin‐enhanced photodetection behaviors. The surface curvature of ZnO nanorod induces pronounced strains for Fe3GeTe2 nanosheet, leading to its anomalous Raman polarization and spin ordering at room temperature. Strain‐activated itinerant spin electrons are immobilized on the O‐2p orbitals of adjacent ZnO, thereby facilitating the optical demagnetization process in Fe3GeTe2 without aid of magnetic field. First‐principles calculations together with in situ characterization experiments further confirm that the primary charge transfer channel involves coupling between Fe3+ and oxygen vacancy defects anchored at heterointerfaces. The rapid establishment of magnetization by illumination in ZnO nanorod contributes to spin‐tunneling‐enhanced photocurrent, device response dynamics, polarization detection and ultraviolet imaging capability. These findings offer valuable insights to optimize the optoelectronic properties of conventional semiconductors and advance complex dimensional spin‐optoelectronic devices. [ABSTRACT FROM AUTHOR]

Current-induced spin–orbit torque (SOT) has attracted much attention due to its potential applications in energy-efficient logic, memory, and artificial neuron devices. In this work, we report an enhanced SOT efficiency in perpendicularly magnetized Pt/Sm/Co/Ta heterostructures by inserting a light rare-earth Sm layer with large spin–orbit coupling. A series of Ta/Pt/Sm/Co/Ta samples with the Sm layer thickness (tSm) of 0, 0.6, 1.2, and 1.6 nm were prepared using direct-current magnetron sputtering. Perpendicular magnetic anisotropy, SOT efficiency, and current-driven magnetization reversal were characterized using electrical transport methods based on the anomalous Hall effect. The experimental results indicated that the switching field and magnetic anisotropic field decreased monotonically with an increase in tSm, while the damping-like effective field and effective spin Hall angle ( θ S H eff ) gradually increased. It demonstrates that interface modification with a Sm layer can improve the SOT efficiency and reduce the pinning potential barrier. Owing to the enhanced SOT and reduced pinning field, the critical switching current density (Jc) exhibits a steady decline when increasing tSm. In particular, the lowest Jc of approximately 7.83 × 106 A/cm2 was obtained when tSm was 1.6 nm. X-ray photoelectron spectroscopy revealed that electron transfer occurred between the Co, Pt, and Sm layers, which may be primarily responsible for the enhanced SOT by interface alloying to effectively strengthen the spin Hall effect of Sm and/or Pt. Our results provide a strategy for improving SOT efficiency and reducing Jc by interface alloying in SOT-based spintronic devices. [ABSTRACT FROM AUTHOR]

Analyzing the magnetization reversal process is crucial for enhancing the magnetic properties of nanocomposite magnets, thereby subsequently increasing the magnetic energy product and advancing the development of next-generation rare earth permanent magnet materials. Here, the open recoil loop is systematically investigated based on micromagnetic simulations and comparing magnetization configurations, which is strongly associated with the asymmetric behavior of weak pinning at the soft/hard magnetic interface. By removing and reapplying field, the irreversible weak pinning sites exhibit asymmetric behavior, leading to the formation of open phenomena in nanocomposites. The open degree of recoil loops obtained from experimental testing was also correlated with the irreversible magnetization, which supports the simulation results. Our findings provide a novel approach for understanding the magnetization reversal mechanism in nanocomposite magnets. [ABSTRACT FROM AUTHOR]

Understanding the magnetization reversal and temperature characteristics of synthetic antiferromagnets (SAFs) is helpful for optimizing the magnetic properties. In this study, a series of synthetic antiferromagnets with perpendicular magnetic anisotropy are deposited. The four stable magnetic states of the SAF are determined by the mutual alignment of magnetic moments in the layers and are controlled by both the magnetic interlayer exchange interaction and Zeeman energy. First order reversal curves were employed to investigate magnetization reversal behaviors and distinguish between reversible and irreversible components. An innovative approach to enhancing the antiferromagnetic coupling field and thermal stability involves introducing a Ru insertion and increasing the thickness of the adjacent magnetic layer. [ABSTRACT FROM AUTHOR]

Due to the magnetostriction effect, a magnetic material changes its dimensions when it is magnetized. In this work, we show how in a magnetostrictive bilayer structure comprising two materials with magnetostriction constants of opposite signs, the magnetic switching is affected by magnetoelastic coupling. While the layer with positive magnetostriction tries to elongate in the direction of the applied magnetic field, the layer with negative magnetostriction tries to contract. In the studied bilayers, the mechanical influence of each magnetostrictive layer on the other is of the opposite sign because of their opposite magnetostrictive constants. Since magnetoelasticity is not an interfacial interaction but an intrinsic property of magnetic materials, the mechanical strain promoted by the applied magnetic field affects the layers as a whole. The net effect is a simultaneous reversal of magnetization of the two layers regardless of their thicknesses. This behavior has been studied in bilayers with different thickness ratios comprising Ni90Fe10, negative magnetostriction and Fe70Ga30, positive magnetostriction. These results demonstrate the possibility of using this physical mechanism to beat the critical limit thickness imposed by interfacial interactions in magnetically coupled multilayers in such a way that the magnetization reversal is made in unison regardless of the layer thickness. [ABSTRACT FROM AUTHOR]

Major hysteresis loops of the F/NM/F/AF structure are classified according to the magnetization process, with the assumption of coherent rotation for each F component and antiferromagnetic coupling between the two F layers. Magnetic stable states of the system as well as specific reversal modes of magnetization during each stage of the major hysteresis cycle are studied in detail based on energetics analysis, in the whole range of exchange bias field and interlayer antiferromagnetic coupling strength. The analysis shows 12 different types of major hysteresis loops for this system and is confirmed by simulation. Strategies to determine key material parameters for the F/NM/F/AF structure from major hysteresis loops are proposed and illustrated by numerical simulation. The research shows a subtle tuning of the magnetization process in the F/NM/F/AF structure, collectively by exchange biasing and interlayer antiferromagnetic coupling. Practically, this serves as a theoretical grounding for the identification of root causes of failure in the product analysis of GMR (giant magnetoresistance) sensors. [ABSTRACT FROM AUTHOR]

Magnetic viscosity experiments have been performed in order to investigate the magnetization reversal in Sr nanoferrite particles (nanoscale SrFe12O19) and interacting Sr/Co nanoferrite particles (SrFe12O19–CoFe2O4 nanocomposites). The magnetic viscosity S = d M (t) / d l n (t) , where M (t) is the magnetization as a function of time, has been collected. For Sr nanoferrite S shows a maximum close to the coercive field, reflecting the relation between S and the energy barrier distribution. We evidence that magnetic viscosity experiments on Sr nanoferrite and interacting Sr/Co nanoferrite particles provide reliable qualitative results for the different magnetic field sweep rate and saturating field H s a t considered. In addition, the activation volumes extracted from the magnetic viscosity experiments performed at different temperatures on Sr nanoferrite are quantitatively correlated to anisotropy changes. [ABSTRACT FROM AUTHOR]

We present a study of the properties related to the magnetization reversal process in two thin-film samples with magnetic stripe domains: Fe0.82Ga0.18 (Fe–Ga) and Ni0.81Fe0.19 (permalloy). In Fe–Ga thin films, we focus on magnetization reversal driven by thermal activation by considering the magnetic viscosity behavior. The results suggest that the reversal process occurs gradually, where the magnetization switches direction via ∼ 10 nm-long jumps of the magnetic domain walls. On the other hand, vectorial hysteresis loops were performed in permalloy thin films with the aim to study the behavior of the transverse magnetization component (perpendicular to the applied field) during the magnetization reversal process. We show that the measurement of the transversal magnetization component shows a much higher sensitivity for the determination of the in-plane magnetic anisotropy than the usual hysteresis loops where the magnetization is parallel to the applied field. Moreover, this allows to highlight the competition between the intrinsic and rotatable anisotropies in thin films that present stripe domains. [ABSTRACT FROM AUTHOR]

Magnetization reversal in a synthetic antiferromagnetically coupled composite of perpendicularly magnetized nanomagnets is theoretically explored based on the macrospin model. The analytical expressions of magnetization reversal are derived. The analytical results are confirmed by the results of the Landau–Lifshitz–Gilbert simulation. Furthermore, we find that a critical antiferromagnetic coupling constant exists at which the dynamics of magnetization reversal changes, and we obtain its analytical expression. This report provides a fundamental analysis insight into antiferromagnetic spintronic phenomena suitable for applications in ultra-high speed devices and nonvolatile memory technologies, for example, state-of-the-art voltage-controlled magnetoresistive random access memory. [ABSTRACT FROM AUTHOR]

We experimentally study magnetization reversal curves for MnTe single crystals, which is the altermagnetic candidate. Above 85 K temperature, we confirm the antiferromagnetic behavior of magnetization M, which is known for α-MnTe. Below 85 K, we observe anomalous low-field magnetization behavior, which is accompanied by the sophisticated angle dependence with beating pattern as the interplay between maxima and minima: in low fields, shows ferromagnetic-like 180° periodicity, while at high magnetic fields, the periodicity is changed to the 90° one. This angle dependence is the most striking result of our experiment, while it can not be expected for standard magnetic systems. In contrast, in altermagnets, symmetry allows ferromagnetic behavior only due to the spin–orbit coupling. Thus, we claim that our experiment shows the effect of weak spin–orbit coupling in MnTe, with crossover from relativistic to non-relativistic net magnetization, and, therefore, we experimentally confirm altermagnetism in MnTe. [ABSTRACT FROM AUTHOR]

This paper presents the results of studies of the effects of magnetoresistance and magnetocapacitance in magnetic tunnel junctions Tb 2 2 − δ Co5 Fe 7 3 /Pr6 O 1 1 / Tb 1 9 − δ Co5 Fe 7 6 with perpendicular anisotropy of magnetic electrodes and a paramagnetic barrier layer. Experimentally measured values of tunnel magnetic resistance and tunnel magnetic capacitance in such contacts exceed 100% at room temperature. The paper analyzes the effect of magnetization reversal of one of the electrodes on the conductivity of magnetic tunnel junctions with electrodes that have perpendicular anisotropy. It is shown that significant changes in tunnel magnetic resistance and tunnel magnetic capacity in such contacts can be explained by the separation of electrons with major and minor spin polarization in the inverse nanolayer in the interface region. The separation of polarized electrons is caused by the magnetomotive force acting on the electron spin in a strongly gradient magnetic field. Such a magnetomotive force occurs with antiparallel magnetization of the magnetic electrodes and it has opposite directions for major and minor polarized electrons. As a result of the spatial separation of polarized electrons in the inversion layer, an inhomogeneous distribution of the electron density along the direction of magnetization of the magnetic contacts occurs. As a result, an additional Coulomb barrier between the magnetic electrodes and the dielectric nanolayer appears in the tunnel contacts and an additional spin capacitance appears. [ABSTRACT FROM AUTHOR]

This study reports the growth and investigation of (001)-oriented MnN/Fe thin films on the W buffer layer, focusing on detailed exchange bias (EB) studies, including thermal evolution (300–10 K) and the training effect. At room temperature, the magnetically annealed α -W/MnN/Fe/Ta stack exhibits an EB field ( H E B ) of 118 Oe. With decreasing temperature, particularly below 100 K, both H E B and coercive field ( H C ) show substantial increases, with H E B displaying a more pronounced enhancement. Analysis of the temperature-dependent H E B and H C data reveals an exponential trend, indicative of a spin-glass-like interface in the MnN/Fe system. At 10 K, the pronounced EB is accompanied by an asymmetric "kinked" magnetization reversal, suggesting a transition from uniaxial to biaxial anisotropy below 50 K due to spin-glass-like magnetic frustration at the interdiffused MnN/Fe interface. Training effect measurements further support the spin-glass-like MnN/Fe interface, with two distinct training mechanisms observed at 10 K: "athermal" and "thermal." Finally, the spin-glass model demonstrates an excellent fit for the training effect data, validating the presence of spin-glass-like disorder at the MnN/Fe interface. [ABSTRACT FROM AUTHOR]

We report the growth, structural characterization, and transport properties of the quantum anomalous Hall insulator Vy(BixSb1−x)2−yTe3 (VBST) grown on a GaAs buffer layer by molecular beam epitaxy on a GaAs(111)A substrate. X-ray diffraction and transmission electron microscopy show that the implementation of a GaAs buffer layer improves the crystal and interface quality compared to the control sample grown directly on an InP substrate. Both samples exhibit the quantum anomalous Hall effect (QAHE), but, with similar thermal stability despite their different structural properties. Notably, the QAHE in the sample grown on a GaAs buffer layer displays a significantly larger (almost double) coercive field with a much smaller resistivity peak at magnetization reversal. Possible effects of the interface quality on the magnetic properties of VBST and the QAHE are discussed. [ABSTRACT FROM AUTHOR]

We report the growth, structural characterization, and transport properties of the quantum anomalous Hall insulator Vy(BixSb1−x)2−yTe3 (VBST) grown on a GaAs buffer layer by molecular beam epitaxy on a GaAs(111)A substrate. X-ray diffraction and transmission electron microscopy show that the implementation of a GaAs buffer layer improves the crystal and interface quality compared to the control sample grown directly on an InP substrate. Both samples exhibit the quantum anomalous Hall effect (QAHE), but, with similar thermal stability despite their different structural properties. Notably, the QAHE in the sample grown on a GaAs buffer layer displays a significantly larger (almost double) coercive field with a much smaller resistivity peak at magnetization reversal. Possible effects of the interface quality on the magnetic properties of VBST and the QAHE are discussed. [ABSTRACT FROM AUTHOR]

Abstract—The collection of paleomagnetic samples of the Lower Devonian Frænkelryggen Formation from the northwest of Spitsbergen is studied. The main carrier of the natural remanent magnetization of the studied rocks is hematite. Based on the component analysis results, the prefolding, bipolar components of the natural remanent magnetization with a positive reversal test are identified. The sequence of the magnetozones of the studied section is compared with the existing world data for Lower Devonian. [ABSTRACT FROM AUTHOR]

We study the process of controlling the states of a magnetic memory cell by a pulsed magnetic field. The magnetization dynamics of such a system is described by the Landau-Lifshitz equation. We find the optimal parameters of time dependence, amplitude and duration of magnetic field pulses created by currents in the control system, which provide a fast inertialess process of switching the magnetization of the functional element of the cell. [ABSTRACT FROM AUTHOR]

Since their first observation in 2017, atomically thin van der Waals (vdW) magnets have attracted significant fundamental, and application-driven attention. However, their low ordering temperatures, Tc, sensitivity to atmospheric conditions and difficulties in preparing clean large-area samples still present major limitations to further progress, especially amongst van der Waals magnetic semiconductors. The remarkably stable, high-Tc vdW magnet CrSBr has the potential to overcome these key shortcomings, but its nanoscale properties and rich magnetic phase diagram remain poorly understood. Here we use single spin magnetometry to quantitatively characterise saturation magnetization, magnetic anisotropy constants, and magnetic phase transitions in few-layer CrSBr by direct magnetic imaging. We show pristine magnetic phases, devoid of defects on micron length-scales, and demonstrate remarkable air-stability down the monolayer limit. We furthermore address the spin-flip transition in bilayer CrSBr by imaging the phase-coexistence of regions of antiferromagnetically (AFM) ordered and fully aligned spins. Our work will enable the engineering of exotic electronic and magnetic phases in CrSBr and the realization of novel nanomagnetic devices based on this highly promising vdW magnet. The discover of van der Waals materials that retain magnetic ordering down to monolayers has fostered considerable interest, however, these materials are often hampered by poor environmental stability. Here, Tschudin, Broadway and coauthors study the magnetic properties of CrSBr, using NV-center based magnetometry, detailing magnetization reversal under applied magnetic fields [ABSTRACT FROM AUTHOR]

The study aims to evaluate the influence of surface modification of Fe powder on the magnetic behavior of soft magnetic compacts and composites that can possibly enhance their properties. The smoothing of ferromagnetic particle surfaces led to a decrease in the total energy loss as the most evident positive impact in all investigated classes (max. by 11% for small, 63–125 μm particle-based annealed Fe compacts, at max. induction 0.5 T and frequency 100 Hz) and to a partial increase in specific electrical resistivity (max. by 47% for small particle-based Fe@SiO2 composites) and resonant frequency (max. by 48% for large, 200–400 μm particle-based Fe@SiO2 composites) as well as partial decrease in coercivity (max. by 14% for small particle-based annealed Fe compacts). Removing surface irregularities negatively affected the maximum total permeability (max. drop by 28% for large particle-based Fe@SiO2 composites) due to increased inner demagnetizing fields. Applying the Bertotti theory for loss separation, we obtained parameters of loss components and assumed the domain structure using simultaneously active magnetic objects as predictors. The total loss decrease observed after the smoothing process originates from the significantly increased numbers of active magnetic objects, facilitating AC magnetization reversal so that domain wall displacements are accompanied by lower energy loss, manifested as a decrease in the excess loss component (max. by 61% for small particle-based Fe@SiO2 composites). [ABSTRACT FROM AUTHOR]

Controlled creation of stable chiral spin textures is required to use them as an energy-efficient information carrier in spintronics. Here we have studied the stable creation of isolated chiral spin texture (skyrmion and antiskyrmion) and its pair through the magnetization reversal of a rectangular nanostructure using spin-polarized currents. An isolated spin texture is created through a negative current pulse. Dynamics of the stable spin texture are explored under external magnetic fields, and the resonant frequencies are calculated. A stable skyrmion pair is created using an asymmetric current pulse, and their interaction is studied using the Thiele equation. The stability of isolated or paired spin texture depends on the Dzyaloshinskii–Moriya interaction strength, spin-polarized current density, and pulse duration. In addition, the stability of the skyrmion pair depends on their initial separation, and a threshold for the separation between skyrmions of 78 nm is observed. [ABSTRACT FROM AUTHOR]

Exchange‐coupled hard–soft bi‐magnetic ferrites can be used as isolators, microwave absorption materials, filters, hyperthermia materials, and biosensors with improved energy properties. The nanocomposites with the chemical composition SrInxFe12‐xO4/Ni0.5Zn05Fe2O4 (where x varies from 0.00 to 0.04) have the advantages of both materials: spinel and hexaferrite. The combination of Sr‐hexaferrate with spinel ferrite results in proximity effects, reversal of magnetization in two stages, and blocking temperatures that can be tuned in bi‐magnetic hard and soft ferrites. It was found an anomalius kink in the hysteresis loops and two peaks in the switching field distribution at x ≤ 0.02. The exchange interaction on the surfaces of hard and soft nanoparticles explains the behavior of the magnetic characteristics. [ABSTRACT FROM AUTHOR]

Paradoxical decision-making behaviours such as preference reversal often arise from imprecise or noisy human preferences. Harnessing the physical principle of magnetisation reversal in ferromagnetic nanostructures, we developed a model that closely reflects human decision-making dynamics. Tested against a spectrum of psychological data, our model adeptly captures the complexities inherent in individual choices. This blend of physics and psychology paves the way for fresh perspectives on understanding the imprecision of human decision-making processes, extending the reach of the current classical and quantum physical models of human behaviour and decision making. [ABSTRACT FROM AUTHOR]

Magnetic thin films with fast magnetization switching and low Gilbert damping are crucial for devices working at high frequency with low power consumption. In this work, composition-controlled high-quality Fe–Ni alloy thin films were electrodeposited on ITO/glass substrates and their magnetization switching behavior was investigated using MOKE and FMR. The phase of deposited alloy transformed from FCC to mixed BCC and FCC for high Fe content films. All the deposited alloy films display granular morphology and possess soft magnetic characteristics with low coercivity (Hc < 50 Oe). Magneto-optic Kerr effect hysteresis along with simultaneous domain imaging reveals that the alloy composition influences anisotropy, domain structure, and magnetization switching process. The alloyed films exhibited fourfold surface anisotropy. The magnetization reversal in pure Fe and Ni samples occurs through stripe-like domains, whereas band and ripple-like domains were evident for the alloyed films. Fast magnetization switching within a minimum field range of ~ 3 Oe was observed for Fe25Ni75 sample. The ferromagnetic resonance measurements revealed that the Fe25Ni75 alloy films exhibit lowest Gilbert damping (α = 0.024) compared to pure Fe and Ni films. In summary, these findings offer valuable insight for tailoring the magnetic properties of Fe–Ni alloy thin films with appropriate alloy composition. [ABSTRACT FROM AUTHOR]

Anomalous Hall effect (AHE) in GdFeCo/Ir/GdFeCo multilayered structures attracts great interest because all optical switching, spin-torque, and other effects promise effective application for ultrafast memory element creation. Since AHE is controlled by GdFeCo magnetization, domain dynamics has importance for practical applications. In our work, magnetization reversal in perpendicular GdFeCo/Ir/GdFeCo synthetic ferrimagnets is characterized by AHE measurements. The AHE hysteresis loop obtained with the field applied perpendicular to the sample plane is composed of three sub-loops, and two of them are symmetrically biased with respect to the third one. Switching magnetic fields for two of the three transitions are found to be dependent on magnetic history. In particular, exposure of the sample in the in-plane field leads to reduction of the out-of-plane switching fields in side sub-loops. A multiple series of perpendicular hysteresis loops recorded after exposure under high in-plane field reveals gradual (within 30 min) relaxation of the out-of-plane switching fields to their initial values observed in a non-magnetized sample. Domain wall mobility, limiting switching of the bilayer devices, is complicated due to the coupling between partial domains in each single layer. Unusual dynamics of double domain walls results in unexpected new phenomena affecting electrical processes in bilayer structures. [ABSTRACT FROM AUTHOR]

Nanopatterned ferromagnetic (FM) thin films have specific characteristics that make them a workhorse for sensors based on magnonic, magnetoplasmonic, or anisotropic magneto-resistive effects. Undulated FM thin films have been studied because of their tunable uniaxial anisotropy. They have been traditionally understood by means of Schlömann's model taking account of shape-induced magnetic anisotropies in softly corrugated systems. Here, we show how it cannot describe accurately the magnetic behavior of highly corrugated FM systems within a thickness region of less than the ripple amplitude. We report on the magnetization reversal processes detected in Permalloy films deposited onto highly corrugated patterns (250 nm in periodicity, 180 nm in amplitude) in a wide thickness range (15–150 nm), finding both that the anisotropy of the system does not correspond to a uniaxial type for FM thicknesses larger than 40 nm and that the anisotropy of the system increases with the FM thickness. Based on the results, we hypothesize that whereas Schlömann's model is valid for softly corrugated thin films, it fails to explain magnetization reversal processes of highly corrugated thin films, especially when the ripple amplitude is much greater than the deposited FM layer thickness. By means of micromagnetic simulations, we find an increment of anisotropy with thickness, just as in the experimental, as well as determine the arise of magnetic domains at the ridges of high thickness corrugated FM thin films. This approach will help to get a better understanding of operating mechanisms in magnetic field sensors based on undulated ferromagnetic materials. [ABSTRACT FROM AUTHOR]

Nanocomposite permanent magnets are considered as a strong candidate for the next generation of high-performance permanent magnet materials due to their ultra-high theoretical magnetic energy product. In this paper, a nanocomposite theoretical model based on the shape anisotropy of the soft phase (Fe65Co35) is constructed to guide the improvement of coercivity, the lack of which has become a critical problem in improving the performance of Nd-Fe-B nanocomposites further. The results of micromagnetic simulation show that adding a shape anisotropic soft phase to nanocomposites can effectively improve coercivity, delay nucleation during the magnetization reversal process, and help obtain a demagnetization curve with high squareness. When the length size of the soft phase ds ≤ 21 nm and the aspect ratio of the soft phase I = 5 for the Nd2Fe14B/Fe65Co35 nanocomposites, almost square demagnetization curves can be obtained, particularly when ds = 21 nm, the size of the soft phase is 21 × 21 × 105 nm3, the content of the soft phase is 42.1 vol. %, and the Nd2Fe14B/Fe65Co35 nanocomposite achieves a maximum magnetic energy product of 94.4 MGOe. In addition, the results also show that, compared with the cubic nanocomposite model (I = 1), the larger size of the soft phase can be accommodated into the nanocomposites by the addition of shape anisotropy, on the premise of ensuring the soft–hard coupling effect. Our design provides a new strategy and approach for preparing high-performance nanocomposite permanent magnets. [ABSTRACT FROM AUTHOR]

Single-phase nanoparticles sample of Y2FeCrO6 double perovskite with an average particle size of 67 nm was prepared and its structural and magnetic behavior is reported. Magnetization vs temperature (M–T) study revealed that the Neel temperature, TN is 327 K, which is greater than the previous finding [Maiti et al., J. Phys. D: Appl. Phys. 46, 415303 (2013)]. Super-exchange interactions in Cr3+–O–Cr3+ and Fe3+–O–Fe3+ networks are responsible for AFM transition. Magnetization reversal (MR) with a high compensation temperature Tcomp = 192 K and sign reversal in both spontaneous and conventional exchange bias fields are observed. In addition, a spin reorientation is observed at TSR ∼ 30 K. At 5 K, a zero-field cooled spontaneous exchange bias (SEB) field of 265 Oe is observed. At the same temperature, after field cooling the sample at 0.5 T, the maximum value of the exchange bias field (CEB) is found to be 2.1 kOe. The SEB shows a sign reversal across TSR, and the CEB reverses its sign across Tcomp. The observed thermal hysteresis of magnetization indicates a first-order phase transition. The loop width of magnetic hysteresis as a function of magnetization exhibits a double peak confirming the multiple magnetic phase behavior. Bipolar switching of magnetization has been demonstrated at 50 K. The competition between single-ion anisotropy and Dzyaloshinsky–Moriya interaction is responsible for the above behaviors. [ABSTRACT FROM AUTHOR]

The magnetic properties, critical behavior, and magnetocaloric effect of perovskite NdMnO3 are studied. The Nd ordering is induced by the Mn ferromagnetic component with antiferromagnetic coupling with each other and then magnetization reversal occurs due to Mn moments reorientation induced by the ordering Nd moments, which explains the phenomenon of negative magnetization at low temperatures. The critical behavior of NdMnO3 is studied using Kouvel–Fisher and self-consistent methods. The results show that the Kouvel–Fisher method is reliable and critical exponents are coming out as β = 0.462 for TC = 11.15 K, γ = 1.041 for TC = 11.42 K, δ = 3.252 by critical isotherm analysis. Magnetic exchange distance may decay as J (r) ≈ r − 4.563 , that is, somewhere between the three-dimensional Heisenberg model and the mean field model. Remarkably, three temperature transitions and the corresponding three extremum values including positive and negative entropy change are observed in NdMnO3, which is different from previous reports on NdMnO3. A positive entropy change as 3.82 J/kg K at 10–15 K for μ0ΔH = 50 kOe and a negative entropy change as −0.557 J/kg K at around 8 K for μ0ΔH = 5 kOe are found, which can be put down to a fast magnetization change of NdMnO3 because of the Nd moments ordering and Mn moments reorientation. Besides, an entropy change of 1.22 J/kg K is found for μ0ΔH = 50 kOe at 80–85 K, which is corresponding to the Mn ferromagnetic ordering temperature. The relative cooling power of NdMnO3 reaches 105.9 J/kg, making it a promising candidate in the field of magnetic refrigeration. [ABSTRACT FROM AUTHOR]

Ni4Nb2O9 displays magnetization reversal, a particular behavior in which magnetization opposes an applied magnetic field. Previous studies have shown that this is caused by the antiferromagnetic coupling of two different layers of ferromagnetic Ni cations. In this work, magnetization reversal is controlled by the substitution of Ni by non-magnetic Zn. Ni4−xZnxNb2O9 materials with x = 0.25, 0.50, and 0.75 maintain the orthorhombic Ni4Nb2O9-type structure but display counterintuitive changes in the magnetic properties including increases in low-temperature net magnetizations, remnant magnetizations, and compensation temperatures. Furthermore, the magnetization reversal is significantly enhanced for x = 0.50 while supressed for x = 0.75, underscoring the strong effects of Zn substitution. [ABSTRACT FROM AUTHOR]

Ni4Nb2O9 displays magnetization reversal, a particular behavior in which magnetization opposes an applied magnetic field. Previous studies have shown that this is caused by the antiferromagnetic coupling of two different layers of ferromagnetic Ni cations. In this work, magnetization reversal is controlled by the substitution of Ni by non-magnetic Zn. Ni4−xZnxNb2O9 materials with x = 0.25, 0.50, and 0.75 maintain the orthorhombic Ni4Nb2O9-type structure but display counterintuitive changes in the magnetic properties including increases in low-temperature net magnetizations, remnant magnetizations, and compensation temperatures. Furthermore, the magnetization reversal is significantly enhanced for x = 0.50 while supressed for x = 0.75, underscoring the strong effects of Zn substitution. [ABSTRACT FROM AUTHOR]

We consider the problem of the magnetization dynamics of a nanosized ferromagnetic sample caused by the spin–orbit interaction of electrons arising in the field of an incident electromagnetic wave. We discuss the case when the frequency of the incident electromagnetic radiation is close to the frequency of the interband transitions. We show that with the use of high-power lasers, this mechanism causes the appearance of a magnetization component perpendicular to the initial magnetization of the sample. This component shows oscillations with a frequency lower than that of incident electromagnetic waves. These dynamics make possible the magnetization reversal of the sample. [ABSTRACT FROM AUTHOR]

Employing an advanced citrate precursor methodology, we successfully synthesized nanoscale spinel ferrites, denoted as Mg 1-x Zn x Fe 2 O 4 (where x ranges between 0.0 and 1.0) or MZFO. Comprehensive analysis, utilizing state-of-the-art X-ray diffraction (XRD) techniques, demonstrated the defining attributes of the crystal structure. All examined specimens consistently exhibited a singular phase, adopting a cubic crystalline architecture. XRD pattern analysis allowed us to deduce the average particle dimensions of these ferrite specimens, which span between 17.2 nm and 31.5 nm. This observed size distribution corroborates well with transmission electron microscopy (TEM) imagery estimations. Delving into the Fourier-transform infrared (FTIR) spectra, two distinctive absorption bands of ferrites emerged: the first between 540 and 570 cm−1 and the subsequent between 339 and 435 cm−1. To glean insight into the electromagnetic attributes of MZFO, we meticulously assessed the experimentally ascertained S-parameters. This scrutiny spanned a frequency spectrum of 8–18 GHz. It was inferred that electromagnetic wave energy dissipation arises chiefly from a combination of electrical and magnetic phenomena. The underlying mechanisms of electrical dissipation can be attributed to polarization processes. Concurrently, the magnetic energy losses predominantly stem from magnetization reversal dynamics. Notably, a substantial attenuation observed in the reflected wave energy, ranging between −10 and −18.5 dB, augments the potential for this material's integration into practical applications. [ABSTRACT FROM AUTHOR]

The magnetization reversal kinetics has been theoretically considered for a nanosized ferromagnetic particle in a soft viscoelastic medium. In contrast to well-known works, we have considered the simultaneous action of the Néel mechanism of magnetization reversal of a particle (overcoming the potential barrier of magnetic anisotropy by its magnetic moment), and rotation (turn) of the particle body as a result of a change in the external magnetic field. The case of a high magnetic anisotropy of the particle is considered, i.e., it has been assumed that its energy significantly exceeds the thermal energy of the system and the energy of the interaction between the particle and the magnetic field. No other limitations have been imposed on field strength. The case of low fields has been considered in greater detail in the linear approximation of the dependence of magnetization on the field. The components of the complex susceptibility of the composite are calculated within the framework of this approximation. It has been shown that the real component of the susceptibility decreases monotonically with the field frequency. If the stiffness of the composite is high or low, the imaginary component has one maximum, which corresponds to the Néel mechanism of magnetization reversal or particle rotation in a viscoelastic medium, respectively. At intermediate values of composite stiffness, the frequency dependence of the imaginary susceptibility has two maxima. [ABSTRACT FROM AUTHOR]

We have investigated the size dependent energy barrier regarding the transition between magnetic vortex and collinear states in dense arrays of magnetic cap structures hosting magnetic vortices. The cap structures were formed by the deposition of soft magnetic thin films on top of large arrays of densely packed polystyrene spheres. The energy barrier associated with the magnetic field assisted switching from a collinear magnetic state to a non-uniform vortex state (or vice versa) was tuned by tailoring the diameter and thickness of the soft magnetic caps. At a sufficient temperature, known as the bifurcation temperature, the thermal energy overcomes this energy barrier and magnetic bistability with a hysteresis-free switching occurs between the two magnetic states. In magnetic caps with a fixed thickness, the bifurcation temperature decreases with increasing cap diameter. On the other hand, for a fixed diameter, the bifurcation temperature increases with an increase in film thickness of the cap structure. This study demonstrates that the bifurcation temperature can be easily tailored by changing the magnetostatic energy contribution which in turn affects the energy barrier and thus the magnetic bistability. [ABSTRACT FROM AUTHOR]

Ultrafast excitation of matter can violate Curie's principle that the symmetry of the cause must be found in the symmetry of the effect. For instance, heating alone cannot result in a deterministic reversal of magnetization. However, if the heating is ultrafast, it facilitates toggle switching of magnetization between stable bit-states without any magnetic field. Here we show that the regime of ultrafast toggle switching can be also realized via a mechanism without relying on heat. Ultrafast laser excitation of iron-garnet with linearly polarized light modifies magnetic anisotropy and thus causes toggling magnetization between two stable bit states. This new regime of 'cold' toggle switching can be observed in ferrimagnets without a compensation point and over an exceptionally broad temperature range. The control of magnetic anisotropy required for the toggle switching exhibits reduced dissipation compared to laser-induced-heating mechanism, however the dissipation and the switching-time are shown to be competing parameters. Toggle switching refers to the switching of magnetization induced by a train of ultrashort laser pulses. The high speed make such switching in extremely promising for devices, however, the underlying toggle switching mechanism in metals is due to heating, and thus has a downside of dissipation. Here, Zalewski et al demonstrate ultrafast 'cold' toggle switching, with a mechanism that does not rely on heating in dielectric Cobalt doped Yittrium Iron Garnet. [ABSTRACT FROM AUTHOR]

Ni nanowire array electrodes with an extremely large surface area were made through an electrochemical reduction process utilizing an anodized alumina template with a pore length of 320 µm, pore diameter of 100 nm, and pore aspect ratio of 3200. The electrodeposited Ni nanowire arrays were preferentially oriented in the (111) plane regardless of the deposition potential and exhibited uniaxial magnetic anisotropy with easy magnetization in the axial direction. With respect to the magnetic properties, the squareness and coercivity of the electrodeposited Ni nanowire arrays improved up to 0.8 and 550 Oe, respectively. It was also confirmed that the magnetization reversal was suppressed by increasing the aspect ratio and the hard magnetic performance was improved. The electrocatalytic performance for hydrogen evolution on the electrodeposited Ni nanowire arrays was also investigated and the hydrogen overvoltage was reduced down to ~0.1 V, which was almost 0.2 V lower than that on the electrodeposited Ni films. Additionally, the current density for hydrogen evolution at −1.0 V and −1.5 V vs. Ag/AgCl increased up to approximately −580 A/m2 and −891 A/m2, respectively, due to the extremely large surface area of the electrodeposited Ni nanowire arrays. [ABSTRACT FROM AUTHOR]

High‐performance and air‐stable single‐molecule magnets (SMMs) can offer great convenience for the fabrication of information storage devices. However, the controversial requisition of high stability and magnetic axiality is hard to balance for lanthanide‐based SMMs. Here, a family of dysprosium(III) crown ether complexes possessing hexagonal‐bipyramidal (pseudo‐D6h symmetry) local coordination geometry with tunable air stability and effective energy barrier for magnetization reversal (Ueff) are shown. The three complexes share the common formula of [Dy(18‐C‐6)L2][I3] (18‐C‐6 = 1,4,7,10,13,16‐hexaoxacyclooctadecane; L = I, 1; L = OtBu 2 and L = 1‐AdO 3). 1 is highly unstable in the air. 2 can survive in the air for a few minutes, while 3 remains unchanged in the air for more than 1 week. This is roughly in accordance with the percentage of buried volumes of the axial ligands. More strikingly, 2 and 3 show progressive enhancement of Ueff and 3 exhibits a record high Ueff of 2427(19) K, which significantly contributes to the 100 s blocking temperature up to 11 K for Yttrium‐diluted sample, setting a new benchmark for solid‐state air‐stable SMMs. [ABSTRACT FROM AUTHOR]

In this study, we investigate the pseudo-static magnetic properties of Permalloy conical frustum nanowires using micromagnetic simulations. We thoroughly examine how both the major and minor radii influence the magnetic reversal mechanism when an external magnetic field is applied parallel to the nanowire axis. The obtained results show that under specific geometrical conditions, magnetization reverts though a Bloch point-type domain wall. In these cases, hysteresis curves exhibit two Barkhausen jumps during magnetization reversal, forming a plateau field range in which a Bloch point domain wall nucleates and propagates until its annihilation after the second Barkhausen jump. The nucleation of a Bloch point domain wall in a frustum conical nanowire geometry is reported. These findings highlight the significance of this geometry in nucleating these attractive topological defects for promising applications. [ABSTRACT FROM AUTHOR]

The interplay of polarization and magnetism in materials with light can create rich nonlinear magneto-optical (NLMO) effects, and the recent discovery of two-dimensional (2D) van der Waals magnets provides remarkable control over NLMO effects due to their superb tunability. Here, based on first-principles calculations, we reported giant NLMO effects in CrI3-based 2D magnets, including a dramatic change of second-harmonics generation (SHG) polarization direction (90°) and intensity (on/off switch) under magnetization reversal and a 100% SHG circular dichroism effect. We further revealed that these effects could not only be used to design ultra-thin multifunctional optical devices but also to detect subtle magnetic orderings. Remarkably, we analytically derived conditions to achieve giant NLMO effects and proposed general strategies to realize them in 2D magnets. Our work not only uncovers a series of intriguing NLMO phenomena but also paves the way for both fundamental research and device applications of ultra-thin NLMO materials. [ABSTRACT FROM AUTHOR]