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The effect of oxygen reduction on the magnetic properties of LaFeO3−δ (LFO) thin films was studied to better understand the viability of LFO as a candidate for magnetoionic memory. Differences in the amount of oxygen lost by LFO and its magnetic behavior were observed in nominally identical LFO films grown on substrates prepared using different common methods. In an LFO film grown on as-received SrTiO3 (STO) substrate, the original perovskite film structure was preserved following reduction, and remnant magnetization was only seen at low temperatures. In a LFO film grown on annealed STO, the LFO lost significantly more oxygen and the microstructure decomposed into La- and Fe-rich regions with remnant magnetization that persisted up to room temperature. These results demonstrate an ability to access multiple, distinct magnetic states via oxygen reduction in the same starting material and suggest LFO may be a suitable materials platform for nonvolatile multistate memory. [ABSTRACT FROM AUTHOR]

The application of Co–Pt thin films as functional elements of novel nanoelectronics and spintronics devices requires the formation of a homogeneous ferromagnetic CoPt phase with tunable magnetic properties. A diffusion-controlled synthesis of this ferromagnetic phase can be implemented through the annealing of deposited Co/Pt bilayers. Apart from thermal treatment, both structural and magnetic properties of such layered stacks can be affected by ion preirradiation. In this work, we, therefore, studied the effect of a two-stage process consisting of preirradiation with 110 keV Ar+/N+ ions followed by post-annealing in vacuum at 550°С for 30 min on the evolution of the structural, chemical, and magnetic properties of Co/Pt/substrate and Pt/Co/substrate heterostructures. The results obtained for such two-stage processing were compared to those received after single-stage vacuum annealing. It was found that when ion preirradiation is followed by annealing, the diffusion-driven intermixing of Pt and Co leading to the formation of the ferromagnetic Co–Pt phase is slowed down compared to the non-irradiated samples, which is associated with the barrier effect of implanted projectiles. Furthermore, we demonstrate that preirradiation does not compromise the magnetic properties of the samples. For instance, preirradiation leads to a coercivity increase of up to 38 % compared to the non-irradiated annealed samples which is attributed to the presence of remaining paramagnetic Pt between the grains of the ferromagnetic A1 -CoPt phase. We demonstrate that the applied two-stage processing (consisting of ion preirradiation followed by thermal annealing) of magnetic thin films is a promising approach for tailoring their magnetic properties such as the in-plane coercivity, saturation, and effective magnetization. • CoPt ferromagnetic thin films are promising materials for spintronics applications. • Two-stage (ion & thermal) processing was employed for the formation of the ferromagnetic phase. • Ion preirradiation followed by thermal annealing caused a slowdown of the intermixing in the Co–Pt stack. • Ion preirradiation induced the coercivity increase of up to 38 %. • Two-stage processing is promising for tailoring magnetic properties of Co–Pt films. [ABSTRACT FROM AUTHOR]

This study considers the equiatomic CoCrNi alloy, a typical multi-principal element alloy (MPEA), which in bulk form, has shown superior mechanical properties and excellent oxidation and corrosion resistance. Such a combination of desirable characteristics motivates further research into the potential use of CoCrNi in thin-film form for various applications. This work aims to grow and optimize the deposition parameters of CoCrNi thin films and investigate their influence on the physical properties. The CoCrNi medium entropy alloy thin films were deposited onto Si/SiO2 substrates by direct current magnetron sputtering at different substrate temperatures and working gas pressures using a pre-alloyed target. The equiatomic polycrystalline composition was obtained at optimized pressure (2 mTorr) and temperature (400 °C). The electrical and magnetic properties were measured and contrasted with the physical properties of the bulk CoCrNi. The obtained magnetic properties indicate stabilization of the ferromagnetic phase in CoCrNi thin films. Anomalous Hall effect has been observed for all studied films. This work shows that deposition conditions (e.g., substrate temperature and working pressure) can be utilized to control the composition and microstructure and tailor the physical properties of the considered MPEA thin films for desired applications. [ABSTRACT FROM AUTHOR]

In this review, the technique of resonant soft X-ray reflectivity in the study of magnetic low-dimensional systems is discussed. This technique is particularly appealing in the study of magnetization at buried interfaces and to discriminate single elemental contributions to magnetism, even when this is ascribed to few atoms. The major fields of application are described, including magnetic proximity effects, thin films of transition metals and related oxides, and exchange-bias systems. The fundamental theoretical background leading to dichroism effects in reflectivity is also briefly outlined. [ABSTRACT FROM AUTHOR]

Magnetic properties of multicomponent alloys depend sensitively on the degree of atomic order on the different crystallographic sites. Here we report the contrast between the magnetic properties of bulk and thin-film samples of the Heusler alloy V 2 FeAl. Arc-melted bulk ingots show no site preference of the elements (A2 structure), whereas magnetron-sputtered thin-film samples display a degree of atomic ordering with a tendency towards XA-type order. Electronic structure calculations favour ferrimagnetic XA-type order, and the effect of different pairwise atomic disorder on the element specific and net magnetic moments are evaluated to reproduce experimental observations. XA-type thin-films with iron moment of 1.24 μ B determined by X-ray magnetic circular dichroism are in agreement with calculation, but the measured net moment of 1.0 μ B per formula unit and average vanadium moment are smaller than expected from calculations. The measured Curie temperature is approximately 500 K. Films with a higher degree of disorder have a lower T C , close to 300 K, with a net moment of only 0.1 μ B at low temperature. The large calculated vanadium moments are destroyed by partial disorder on 4 d vanadium sites. By contrast, the arc-melted and annealed bulk alloy with a fully-disordered A2 structure shows no spontaneous magnetization at any temperature; it is a Pauli paramagnet with dimensionless susceptibility χ v = 2.95 × 10-4. [Display omitted] [ABSTRACT FROM AUTHOR]

The recent developments in the study of magnetic properties in the spinel zinc ferrite system are explored. Engineering of ionic valence and site distribution allows tailoring of magnetic interactions. Recent literature is reviewed, and own investigations are presented for a conclusive understanding of the mechanisms responsible for the magnetic behavior in this material system. By varying the Zn‐to‐Fe ratio, the deposition, as well as thermal annealing conditions, ZnFe2O4 thin films with a wide range of crystalline quality are produced. In particular, the focus is on the magnetic structure in relation to spectroscopic properties of disordered ZnFe2O4 thin films. Comparing the cation distribution in film bulk (optical transitions in the dielectric function) and near‐surface region (X‐ray absorption), it is found that an inhomogeneous cation distribution leads to a weaker magnetic response in films of inverse configuration, whereas defects in the normal spinel are likely to be found at the film surface. The results show that it is possible to engineer the defect distribution in the magnetic spinel ferrite film structure and tailor their magnetic properties on demand. It is demonstrated that these properties can be read out optically, which allows controlled growth of the material and applications in future magneto‐optical devices. [ABSTRACT FROM AUTHOR]

The magnetic and magnetoresistance properties of multilayered structures consisting of two different combinations of magnetic and nonmagnetic IrMn, Co, Cu, Ni, Py thin layers were studied in the temperature range of 10–300 K. Thin films were prepared by using conventional magnetic sputtering techniques in ultra-high vacuum conditions. The structural characterization was examined by X-ray reflectivity. Magnetic and electrical properties were studied by conventional dc magnetization and 4-probe resistivity measurements. A close relationship between magneto resistivity and the relative behavior of magnetic hysteresis of adjacent magnetic layers was observed. Very abrupt stepwise changes at coercive field regions of the soft magnetic layers were attributed to the so-called giant magnetoresistance effect at low temperatures in both combinations of the layers. [ABSTRACT FROM AUTHOR]

Magnetic thin films of Fe/Cu/Fe and Fe/Cu/Ni multilayers on glass substrates were deposited by thermal evaporation route. The structure and morphology of multilayers were studied by X-ray diffraction (XRD) and atomic force microscopy (AFM). Amorphous formation of the Fe and Ni in multilayer structures and the maximum surface roughness of about 6.11 nm for the Fe/Cu/Fe and 4.8 nm for the Fe/Cu/Ni thin films were observed. Also, magnetization behaviors in perpendicular and parallel fields to the surface were investigated. The behavior of the magnetization indicates a low 5-mT coercive field, the easy in-plane magnetization, and the formation of soft ferromagnetic structure. The giant magneto-impedance response (GMI) to the applied longitudinal magnetic field at 5-MHz frequency was obtained 70% for three-layer Fe/Cu/Fe. Also, the measurements for the Fe/Cu/Ni film show a peak in the external field of about Hext = 14 Oe and the GMI response of about 95% at 5-MHz frequency. This work provides a preliminary investigation into the high performance of multilayer-based GMI devices for sensor applications. [ABSTRACT FROM AUTHOR]

• Perpendicular magnetic anisotropy (PMA) in CoPt/CoO x bilayers has been enhanced. • The CoPt/CoO x bilayers show strong perpendicular exchange bias (PEB). • The thin CoO x layer has been formed with Co at different oxidization state. • Up to Q = 20%, the oxidization of Co in CoO x layer monotonously promotes the PMA. • The strongest PEB occurs at Q = 10% due to the phase transition of CoO x layer. The magnetic properties of the CoPt/CoO x bilayers have been investigated in this work. Compared with the CoPt single layer, enhanced perpendicular magnetic anisotropy (PMA) and strong perpendicular exchange bias (PEB) have been observed in the CoPt/CoO x bilayers. The thin CoO x layer with Co at different oxidization state, formed by controlling the oxygen gas flow rate ratio in the oxygen and argon gas mixture during the magnetron sputtering, has been found to significantly affect the magnetic anisotropy and exchange bias of the films. Up to 20% oxygen flow rate ratio, the oxidization of Co in CoO x layer monotonously promotes the PMA. While the maximum value of PEB is obtained at 10% oxygen flow rate ratio, and then decreases for further oxidation due to the phase transition from CoO to Co 3 O 4 with a smaller AFM anisotropy constant. Our study provides useful information for fabricating and understanding ferromagnet/antiferromagnet thin films with strong perpendicular magnetic anisotropy and perpendicular exchange bias. [ABSTRACT FROM AUTHOR]

Highlights • Pt/Co/Pt trilayers were irradiated quasi-uniform with FIB. • Irradiations were done by square spiral scanning. • Out-of-plane magnetization was observed for two fluence ranges. • Easy axes are inclined to the plane and perpendicular to the fast scanning direction. Abstract Focused ion beam (FIB) irradiation was applied to an ultrathin Pt/Co/Pt film to create micrometer-sized, square-shaped regions with perpendicular orientation of magnetization embedded in an in-plane magnetized environment. The FIB parameters like ion fluence and scanning direction are used to control the magnetic properties of the irradiated areas. We have studied the magnetic and magnetooptical properties in the irradiated areas as a function of ion fluence by means of component selective magnetooptical Kerr microscopy that measures separately pure polar and pure longitudinal components of magnetization. Two fluence ranges that induce perpendicular magnetization components were observed. In the higher fluence range, four regions with independently inclined out-of-plane magnetization, depending on FIB fast scan direction, and an unexpected magnetic domain structure were distinguished inside the squares irradiated by FIB. [ABSTRACT FROM AUTHOR]

The effect of thickness on structural and magnetic properties of Co-rich Bi10Co16O38 (BCO) sillenite thin films is investigated systematically. BCO thin films are deposited using a simultaneous evaporation of Bi2O3, Co targets with RF-DC magnetron sputtering along with post-annealing procedure. The magnetic studies reveal an ordered magnetic nature below film thicknesses of 100 nm. Further, the temperature-dependent and field-dependent magnetic data is evaluated to comprehend the microstructure impact on to the magnetic nature of Co-rich sillenite thin films. [ABSTRACT FROM AUTHOR]

New ferromagnetic films with composition SiC x N y Fe z were synthesized using chemical vapor deposition technique. Films were deposited using ferrocene, 1,1,1,3,3,3-hexamethyldisilazane (HMDS) and hydrogen gaseous mixture. Chemical and phase composition of the films were studied by FTIR, Raman spectroscopy and X-ray diffraction with grazing incidence (GI-XRD). FTIR spectra analysis confirmed the existence of Si-C and Si-N bonds. Graphite inclusions and amorphous carbon were determined by Raman spectra analysis. The surface of the SiC x N y Fe z films studied by SEM is covered by nanocrystallites of iron oxide Fe 3 O 4 phase. The main purpose of GI-XRD analysis is to describe the layered structure of the films in detail. It was shown by GI-XRD study, that phase composition of the SiC x N y Fe z films varies from iron oxide Fe 3 O 4 to iron silicide Fe 3 Si and silicon carbide SiC with the deposition temperature growing. It was established, that SiC x N y Fe z films are perspective for application in the spintronic field. [ABSTRACT FROM AUTHOR]

Multi-layers of Co 20 Fe 60 B 20 and Pt with large perpendicular magnetic anisotropies (PMA), comparable to those obtained with the more widely utilized Ta/CoFeB/MgO heterostructures, are reported. CoFeB thickness of approximately 0.8 nm is necessary to maximize PMA in Pt/CoFeB/Pt. Strong PMA can only be obtained upon careful tuning of the material the CoFeB layer is deposited on. Specifically, a Pt layer thickness of at least 3 nm is necessary to obtain PMA in CoFeB due to the emergence of (111) texture in thicker Pt films. The absence of a magnetic dead layer at the interface between CoFeB and Pt (as opposed to an interface between CoFeB and Ta) maximizes the amount of magnetic content per unit volume. Furthermore, this study investigates the magnetic properties of multi-layer structures where four CoFeB layers are deposited between Pt and Pt/Ta/Pt buffers. While the out-of-plane remanent magnetization of the structures is low, they present small nucleation field down to 30 Oe and large anisotropy energy in the range of 106 erg/cc. • Large perpendicular magnetic anisotropy in Pt/Co 20 Fe 60 B 20 /Pt, similar to Ta/CoFeB/MgO. • Texture of Pt underlayer affects perpendicular magnetic anisotropy of Co 20 Fe 60 B 20. • No magnetic dead layer is found at the interfaces between Co 20 Fe 60 B 20 and Pt. [ABSTRACT FROM AUTHOR]

• Evolution of phase transitions in Pt/Fe/Pt/Au/Fe and Pt/Fe stacks upon annealing. • Reduction of annealing temperature and time needed for chemical L1 0 ordering onset. • Enhancement of coercivity via Au layer introduction. • Coexistence of soft and hard magnetic phases after annealing. • Pathway to create exchange graded magnetic nanomaterials. Intermetallic compound formation realized via thermally-induced diffusion intermixing of layered stacks is a prospective route for the formation of thin films with properties promising for practical applications. This can be further promoted by the addition of third elements which could provide acceleration of diffusion and ordering processes during post-annealing. In the present study, we have investigated the structural and magnetic properties of post-annealed Pt/Fe/Pt/Au/Fe thin films which contain an additional asymmetric Au layer and compare the results with Fe/Pt bilayers. It was shown that the introduction of an Au layer reduces both the onset temperature and the annealing time for promoting the formation the hard magnetic L 1 0 -FePt phase while the remaining layer stack develops a magnetically soft Pt-rich disordered FePt solid solution. Thus, different diffusion pathways present in asymmetric layer stacks can provide an intriguing root for thin film materials synthesis of exchange coupled soft and hard magnetic phases which could be of particular interest for the creation of graded magnetic nanomaterials. [ABSTRACT FROM AUTHOR]

Cobalt nitride has been prepared and studied for magnetic memory applications. Sol-gel technique is used to prepare thin films of cobalt nitride. The films were deposited onto substrates by spin coating at 3000 rpm for 30 s. The films were then air dried and heated at 300°C for 120 min. As-deposited and heated samples were characterized for their structural and magnetic properties using X-ray diffractometer (XRD) and vibrating sample magnetometer (VSM) techniques. The grain size was in the range of 22.7-30.10 nm. Their surface was studied by scanning electron microscopy (SEM). Orthorhombic structure can be seen in SEM micrographs. This orthorhombic structure is also confirmed by XRD. [ABSTRACT FROM AUTHOR]

Multilayer films were sputtered on Si (100) substrate by following a layer sequence of Cr (10nm)/[Fe (4nm)/SmCo5 (20nm)]11/Cr (90nm) at room temperature and subsequently, subjected to two-stage annealing. The phase composition, the extent of inter-diffusion at the SmCo5/Fe interfaces and the magnetic properties of multilayered samples were investigated by X-ray diffraction (XRD), RBS and super-conducting quantum interference device (SQUID), respectively. The XRD studies showed the crystallization of SmCo5-phase in the hard layer along with a bcc-Fe (Co)-phase in the soft layer, while the RBS depth profile analysis revealed the changes that occur in the effective Fe-layer thickness and diffused Co-content as minimal for the Fe-layer index, nFe≤5. A single-phase behavior associated with strong in-plane anisotropy was evidenced with the SQUID measurements. The observed remanence enhancement (1020kA/m) and energy product value (286kJ/m³) in these multilayers are discussed in the context of Fe-layer thickness and diffused Co-content. [ABSTRACT FROM AUTHOR]

[Display omitted] • Polycrystalline ferromagnetic films created by Fe ion implantation in 60 nm Pd. • Magnetic moments up to 4.8 Bohr magnetons per implanted Fe atom. • New model for net magnetic moment reproduces data with explainable deviations. • Fe concentration depth profile connected to magnetization. • Prediction and engineering of magnetic properties on nanometer scale is enabled. Ferromagnetic thin films were synthesized by implantation of Fe ions with energies between 40 keV and 120 keV in 60 nm of polycrystalline Pd. The possibility to engineer magnetic properties in such films through the Fe concentration depth profile was demonstrated. In-plane magnetic moments were measured both while varying the sample temperature at constant applied magnetic field, and varying the applied field at constant temperature. All samples were explicitly shown to exhibit ferromagnetism at sufficiently low temperature, with threshold temperatures in the range from 35 K to 140 K. Saturation moments at 5 K were between 3.5 and 4.6 Bohr magnetons per implanted Fe atom for implantation fluences between 5 × 1015 and 2.3 × 1016 ions/cm2. Coercivities were between 1 and 3 mT. The samples included in the study were carefully characterized with Rutherford backscattering spectrometry, and selected samples with elastic recoil detection analysis and cross-sectional transmission electron microscopy, providing information on Fe concentration profiles, impurity fractions, structure as well as sample modification during implantation. A new model was proposed to calculate the scaling of the films' magnetic moments with temperature from the Fe concentration profiles. The model qualitatively reproduced the data and quantitative differences were explained. It can thus be applied to predict the modification of the magnetic moment at a given temperature for a similar film when the implantation parameters are varied. [ABSTRACT FROM AUTHOR]

Abstract: In this work we have investigated (Fe3Ga/TbFe2) n multilayers grown by sputtering at room temperature. These multilayers exhibit a large coercivity associated to the crystalline TbFe2 Laves phase. To reduce the coercivity it is necessary to control the crystallization of that material. In this work, we focus on the analysis of the properties of the TbFe2 layers. In the as-grown heterostructures we have found evidence of nanoaggregates in the TbFe2 layers. The Fe3Ga thickness and the thermal treatments have an influence on the volume of these nanoprecipitates. In the annealed samples, when increasing the Fe3Ga thickness we observe a decrease in the nanoaggregate volume and thus in the coercivity. The experimental results indicate that the crystallization of the TbFe2 depends on the Tb diffusion promoted by the thermal treatment and on the stiffness factor (Y/α) of the Fe3Ga layer. The magnetostrictive properties are also strongly influenced by the crystallization of the TbFe2. We have achieved a maximum magnetostriction constant of nearly 550ppm with a coercive field close to 400 Oe. [Copyright &y& Elsevier]

Abstract: The measurement of the force per width of CoCrX(X = Pt, Ta)/CrTi bilayer showed that both the surface structure state and surface stress of CoCrX magnetic layer can be controlled by regulating the average film stress of CrTi underlayer through a variation of deposition conditions such as deposition rate and temperature as well as underlayer thickness. As the tensile surface stress of CoCrX magnetic layer was more, its coercivity was also more. This was because not a dynamic phase decomposition with a compressive ledge due to high adatoms mobility but an epitaxial film growth with a tensile ledge due to low adatoms mobility. Thus, the development of the crystallographic texture of CoCrX alloy can largely improved its coercivity. It is believed that the principal mechanism determining the coercivity of CoCrX/CrTi film is the optimized development of the crystallographic texture through an evolution of the surface stress of CrTi underlayer. [Copyright &y& Elsevier]

g/[BN/CoPt]/Ag and [BN/Ag/CoPt]/Ag thin films were deposited on glass substrates by magnetron sputtering and then annealed in vacuum at 600°C for 30 min. The structures and magnetic properties of CoPt/BN multilayer films were investigated as a function of Ag layer thickness. It was found that the face-centered tetragonal (fct) (001) texture of CoPt was improved greatly by introducing the Ag toplayer or sublayer together with an Ag underlayer. Good (001)-oriented growth, low intergrain interactions as well as high perpendicular anisotropy can be obtained in the Ag(3 nm)/[BN(2.5 nm)/CoPt(3 nm)]/Ag(7 nm) and [BN(2.5 nm)/Ag(2 nm)/CoPt(3 nm)]5/Ag(10 nm) films, which become potential candidates for ultrahigh density magnetic recording media. [ABSTRACT FROM AUTHOR]

Abstract: The influence of sulphur incorporation during electrodeposition on the structural and magnetic properties of both Co and Co–Ag thin films from aqueous thiosulphate solutions has been investigated. Co–Ag deposits containing sulphur showed granular morphology and varying cobalt and sulphur contents as a function of the applied potential. Nanocrystalline soft-magnetic deposits whose coercivity decreased as sulphur incorporation increased were obtained. More influence of the sulphur presence on the cobalt thin film magnetic properties was observed due to the significant structural changes induced by sulphur incorporation into the crystalline lattice. When high amounts of S were present, soft-magnetic amorphous cobalt coatings were obtained. On the other hand, stronger hard-magnetic behaviour was detected on those crystalline thin films where S content was lesser. [Copyright &y& Elsevier]

We have studied structural, electrical, and magnetic properties of Ni and Ni78Fe22 thin films evaporated on polyethylene naphtalate (PEN) organic substrates towards the fabrication of spin quantum cross (SQC) devices. As we have investigated the scaling properties on the surface roughness, the surface roughness of Ni (16 nm)/PEN is 0.34 nm, corresponding to 2 or 3 atomic layers, in the scanning scale of 16 nm, and the surface roughness of Ni78Fe22 (14 nm)/PEN is also as small as 0.25 nm, corresponding to less than 2 atomic layers, in the scanning scale of 14 nm. These facts denote that Ni/PEN and Ni78Fe22/PEN are suitable for magnetic electrodes on organic substrates used for SQC devices from the viewpoint of the surface morphology. Then, we have investigated magnetic hysteresis curve and magnetoresistance effects for Ni/PEN and Ni78Fe22/PEN. The squareness of the hysteresis loop is as small as 0.24 for Ni (25 nm)/PEN, where there is no observation of the anisotropy magnetoresistance (AMR) effect. In contrast, the squareness of the hysteresis loop is as large as 0.86 for Ni78Fe22 (26 nm)/PEN, where the AMR effect has been successfully obtained. These experimental results indicate that Ni78Fe22/PEN is a promising material for use in SQC devices from the viewpoint of not only the surface morphologies but also magnetic properties. [ABSTRACT FROM AUTHOR]

Abstract: A correlation between composition, microstructure, and magnetic properties of sputter-deposited CoFeSiB alloy films has been studied. Various analytical tools and micromagnetic models were employed to understand the details of microstructural evolution and magnetic reversal processes, respectively. The CoFeSiB alloy film shows significantly different microstructure and magnetic properties depend on the Co concentration. When the Co concentration is below 75 at.%, the alloy has an amorphous phase exhibiting magnetic softness with negative remanence. Meanwhile, beyond 75 at.%, the structure consists of nanocrystals precipitated in the amorphous matrix, which becomes magnetically hard with positive remanence as well as antiferromagnetic exchange coupling. [Copyright &y& Elsevier]

This paper reports an investigation of the structure, magnetic phase transition and magneto-optical properties of FeRh0.95Pt0.05 thin film. A first-order magnetic phase transition occurs at a temperature around 180°C, accompanied by a lattice expansion in the c-axis. The effect of substitution on the phase transition in ordered FeRh-based alloy systems is discussed. The nucleation and growth mechanism of the phase transition is quite similar to that of the crystallization of solids. In addition, the Kerr rotation spectrum was also studied. [Copyright &y& Elsevier]

The magnetic and transport properties of pulsed laser-deposited Co100−x–Cux thin films were tailored through their nano-morphology and composition by controlling for the deposition geometry, namely normal or oblique deposition, and their Cu content. All films were composed of an amorphous Co matrix and a textured growth of Cu nanocrystals, whose presence and size d increased as x increased. For x = 50, all films were superparamagnetic, regardless of deposition geometry. The normally deposited films showed no in-plane magnetic anisotropy. On the contrary, controllable in-plane uniaxial magnetic anisotropy in both direction and magnitude was generated in the obliquely deposited films. The magnetic anisotropy field Hk remained constant for x = 0, 5 and 10, Hk ≈ 35 kAm−1, and decreased to 28 and 26 kAm−1 for x = 20 and 30, respectively. This anisotropy had a magnetostatic origin due to a tilted nano-sheet morphology. In the normally deposited films, the coercive field Hc increased when x increased, from 200 (x = 0) to 1100 Am−1 (x = 30). In contrast, in obliquely deposited films, Hc decreased from 1500 (x = 0) to 100 Am−1 (x = 30) as x increased. Activation energy spectra corresponding to structural relaxation phenomena in obliquely deposited films were obtained from transport property measurements. They revealed two peaks, which also depended on their nano-morphology and composition. [ABSTRACT FROM AUTHOR]

Cobalt thin films deposited by radio frequency sputtering were investigated. Microstructures of the Co films were analyzed by XRD and TEM. The results show that films microstructure varies with the variation of the sputter gas pressure PAr. Magnetic properties measured by VSM show that all the films possess relatively high saturation magnetization 4πMs, and strong in-plane uniaxial magnetic anisotropy field Hk. Co films deposited below 0.3 Pa show soft magnetic properties and its microwave permeability was measured by vector network analyzer in the 0.1–5 GHz range. [ABSTRACT FROM AUTHOR]

Abstract: The crystal structure of reactive sputtered Mn x Ti1− x O2 films turns from anatase to rutile as x increases. All the films are ferromagnetic, with a Curie temperature above 340K. Vacuum annealing enhances the ferromagnetism of the films, but O2 annealing weakens it, indicating that the ferromagnetism is related to the oxygen-vacancy defects created by Mn+2 dopants at Ti+4 cations. The average room-temperature moment per Mn decreases from 0.482μB at x =0.026 to 0.078 μB at x =0.375. Meanwhile, the optical band gaps value decreases linearly from 3.35eV at x =0 to 1.73eV at x =0.375, suggesting that Mn ions substitute for Ti ions uniformly and the ferromagnetism is not from magnetic Mn oxide impurities. The high-temperature ferromagnetism makes the Mn x Ti1− x O2 films useful for the applications in spintronic devices. [Copyright &y& Elsevier]

Abstract: FePd thin films were electrodeposited from ammonium citrate complex baths. The effects of various electrodeposition and post heat treatment conditions including pH, current density, bath concentrations, substrates and annealing temperature on composition, material, and magnetic properties were systematically investigated. In these baths, the deposited iron content increased linearly with an increase in current density from 1 to 5mAcm−2 producing films with compositions extending from Fe7Pd93 to Fe91Pd9. Magnetic saturation (M S) of electrodeposited FePd thin films linearly increased with increase in deposited iron content (i.e. ∼1.8T for Fe82Pd18 and ∼0.1T for Fe19Pd81) which is similar to its bulk counterparts. The effects of post-heat treatment on the phase and crystal structure of near equiatomic FePd electrodeposits (i.e. Fe48Pd52) was investigated by subjecting electrodeposits to different annealing temperatures from 400 to 600°C under reducing environment. L10 FePd phase was formed from nanocrystalline FePd solid solution and the crystallinity improved with increasing annealing temperatures. [Copyright &y& Elsevier]

Abstract: We have studied the effects of ion irradiation on the structural and magnetic properties of FeCo/Cu multilayers. The films were irradiated at room temperature with 600keV Kr ions, with fluences ranging from 1 to 5×1015 ions/cm2. X-ray absorption spectroscopy (XAS) was used to characterize the structural changes around Fe and Co atoms. The XAS data have shown a phase transformation of FeCo alloy from bcc for the as-deposited sample to fcc after irradiation. The structural effects induced by irradiation changed the saturation magnetization (M S), the coercive field (H C) and the magnetic particle size. The interplay between structural and magnetic effects indicates that some degree of mixing took place even being the elements immiscible. [Copyright &y& Elsevier]

This paper presents the magnetic properties of CoFeB trilayer thin films in relation to the high-frequency impedance responses. Fifty- and 100-nm-thin amorphous layers with a central 100- and 200-nm-thin Cu layer, respectively, were sputtered onto a thermally oxidized Si wafer. 300-mum-long meanders of 3-20-mum width were structured using a standard mask with various meanders, which were connected in series and were then formed by plasma etching. Magnetization curves, parallel to the easy axis, and hard axis of uniaxial anisotropy, were measured by the magnetooptical Kerr effect exhibiting anisotropy fields of around 2 kA/m and low coercivity in the hard-axis direction, depending on the film thickness. The magnetoimpedance (MI) effect was measured manually from 10 MHz to 1 GHz by means of a network analyzer using the reflected wave through the sample. The maximum effect occurred for both samples at 850 MHz [ABSTRACT FROM PUBLISHER]

The surface layer of an epitaxial Fe/Cr multilayer system has been structured lithographically into stripes with 1 μm period. Polarized neutron reflectometry and diffuse scattering under grazing incidence measurements show strongly enhanced domain formation compared to the unstructured sample. The domains are correlated throughout the layers. The lateral domain size is partly the period of the stripe pattern of the surface layer, and partly the double. [Copyright &y& Elsevier]

We discuss the possibility of attaining more than 1 Gb/in2 recording in helical scanning tape storage system based on obliquely oriented metal evaporated tapes. A demonstration of 1 Gb/in2 recording using an inductive MIG type head is described. Other experimental results show that the obliquely oriented Co-O tapes are endowed with recording resolution potential beyond several Gb/in2, but playback signal-to-noise challenges still remain. Applying more sensitive magneto-resistive heads in the helical scanning tape system requires significant innovation in the system to overcome crucial issues of contact recording as well as re-optimization of the magnetic properties of the tape. [ABSTRACT FROM PUBLISHER]

The thermal stability of data stored in thin film recording media is closely tied to signal-to-noise ratio (SNR), yet is not correlated in a simple way. Indeed grain size strongly affects both SNR and thermal stability, but macroscopic magnetic properties as well as recording conditions are equally influential. This is illustrated by measurements of SNR and signal thermal decay along with a simple model analysis. Dependence of areal density on key magnetic properties, under SNR and stability constraints, is formulated. [ABSTRACT FROM PUBLISHER]

Compositional and temperature dependencies of saturation magnetization (Ms) and uniaxial magnetocrystalline anisotropy (Ku) are determined using single crystal CoCr-alloy thin films. Temperature dependencies of Ms and Ku are stronger with increasing Cr content. Ms(OK) and Curie temperature (Tc) decrease linearly with increasing Cr content in a Co-Cr-X (X=Ta, Pt) system. Ms(OK) and Tc become zero at the Cr concentration of 33 at.%, Co-Cr-Pt specimens have higher Tc and higher Ku than those of Co-Cr-Ta specimens with similar Cr concentration. The magnetic properties of polycrystalline medium are confirmed to depend strongly on those of Co-rich core crystalline grains in Cr segregated microstructure. [ABSTRACT FROM PUBLISHER]

This work demonstrates the dependence between magnetic properties and the thickness of NiFe thin films. More importantly, a quantitative study of the surface composition of NiFe thin film exposed to atmospheric conditions has been carried out employing angle-resolved X-ray photoelectron spectroscopy (ARXPS). In this study, we fabricated Ni81Fe19 (NiFe) thin films on Si (100) substrate using electron beam evaporation and investigated their surface morphologies, magnetic properties, and the thickness of the surface oxide layer. The coexistence of metallic and oxidized species on the surface are suggested by the depth profile of ARXPS spectra. The thickness of the oxidized species, including NiO, Ni(OH)2, Fe2O3, and Fe3O4, are also estimated based on the ARXPS results. This work provides an effective approach to clarify the surface composition, as well as the thickness of the oxide layer of the thin films. [ABSTRACT FROM AUTHOR]

• Thickness dependent magnetic anisotropy in Tb-Fe thin films studied. • Formation of nano-columnar structures aid perpendicular magnetic anisotropy. • The magnetic energetics changes from surface dominated to bulk-lie properties with increase in film thicknesses. In this paper, we have attempted to understand the magnetic behaviour of Tb-Fe thin films grown with different thicknesses through detailed electron microscopy, magnetization measurements and magnetic domain imaging studies. Tb-Fe thin films over a range of thicknesses such as 50, 100, 200, 400, 600 and 800 nm were deposited on Si<100>substrates using electron beam evaporation technique. Grazing incidence X-ray diffraction studies revealed that all the films were amorphous in nature. Microstructural studies using transmission electron microscopy showed columnar channel of voids extending from substrate to film surface. Magnetization measurements along the in-plane and out-of-plane direction indicated presence of out-of-plane magnetic anisotropy in all the films. Saturation magnetization and coercivity measured along the out-of-plane direction were found to vary with the thickness of the films. A very high coercivity of ~2000 mT was obtained for the film having thickness of 400 nm. Magnetic anisotropy calculations indicated a strong perpendicular magnetic anisotropy for the 400 nm thick film. The variation of magnetic anisotropy with film thickness was correlated with the magnetic domain patterns observed in the films using magnetic force microscopy. [ABSTRACT FROM AUTHOR]

Two different lithographic techniques have been developed for fabricating magnetic nano-elements on ultra-thin electron-transparent substrates thereby allowing transmission electron microscopy to be used to investigate their properties. Here we describe studies of elements of micropolycrystalline Permalloy and cobalt whose thicknesses lie in the range 20-30 nm. Bright field images show that a high degree of edge acuity is attained and elements with lateral dimensions /spl ap/25 nm have been produced. Lorentz microscopy has provided unique insight into the detailed magnetisation reversal mechanisms in acicular elements with widths in the range 100-300 nm. In cobalt elements a single domain occupies most of the volume with complex domain structures existing very close to the ends; switching fields increase markedly with decreasing element width but are substantially independent of element length. The reversal mechanism is found to involve the propagation of a small "reversing" domain structure along the element length. In Permalloy, extensive domain structures are observed in all but the narrowest elements in the remanent state. The response to applied fields is described. [ABSTRACT FROM PUBLISHER]

Magnetic properties of c-axis uniaxially in-plane aligned Ba-ferrite thin films were studied. Ba-ferrite thin films on [110] a-plane single-crystal sapphire substrates were deposited by low-power RF diode sputtering. Different degrees of grain isolation were achieved via postdeposition annealing at various temperatures in a rapid thermal annealing furnace. In this study, a magnetic evaluation of intergranular interaction was carried out using the well-established remanent magnetization /spl Delta/M curve. The results presented indicate a positive magnetostatic interaction, the strength of which is correlated with grain separation when measured along the magnetic easy axis direction. A predominant negative magnetostatic interaction was observed when measured along the magnetic hard axis direction, the magnitude of which is relatively independent of further grain separation. [ABSTRACT FROM PUBLISHER]

The Ni 2 Mn 1 + x Z 1 − x Heusler alloys, where Z = In, Sn,Sb are attractive candidates for shape memory applications. The effect is directly related to their magnetic properties. We have studied these systems by ab-initio calculations and experiments, focusing on magnetic moments and exchange-bias fields. The calculations indicate that the composition dependence of the total magnetic moment is due to competing ferromagnetic and antiferromagnetic alignment between Mn atoms on different sublattices and with different local environments. This phenomenon can also explain the composition dependence of the exchange-bias effect. [ABSTRACT FROM AUTHOR]

The ability to induce and control the perpendicular magnetic anisotropy (PMA) of ferromagnetic layers has been widely investigated, especially those that offer additional functionalities (e.g., skyrmion stabilization, voltage-based magnetization switching, rapid propagation of domain walls). Out-of-plane magnetized ferromagnetic layers in direct contact with an oxide belong to this class. Nowadays, investigation of this type of system includes antiferromagnetic oxides (AFOs) because of their potential for new approaches to applied spintronics that exploit the exchange bias (EB) coupling between the ferromagnetic and the AFO layer. Here, we investigate PMA and EB effect in NiO/Co/Au and NiO/Co/NiO layered systems. We show that the coercive and EB fields increase significantly when the Co layer is coupled with two NiO layers, instead of one. Surrounding the Co layer only with NiO layers induces a strong PMA resulting in an out-of-plane magnetized system can be obtained without a heavy metal/ferromagnetic interface. The PMA arises from a significant surface contribution (0.74 mJ/m2) that can be enhanced up to 0.99 mJ/m2 by annealing at moderate temperatures (~450 K). Using field cooling processes for both systems, we demonstrate a wide-ranging control of the exchange bias field without perturbing other magnetic properties of importance. [ABSTRACT FROM AUTHOR]

This study examined the structural, magnetic, and transport properties of CoFeSiB films with various Co compositions. The main focus was on two samples, amorphous Co74Fe4Si14B8 and nanocrystalline Co78Fe2Si12B8 thin films. The results show that the amorphous film is a typical soft magnetic material, while the nanocrystalline film has a large saturation field. It is believed that in a nanocrystalline thin film, a large saturation field is caused by antiferromagnetic exchange at the boundary between the amorphous and nanocrystalline phases. [ABSTRACT FROM PUBLISHER]

Abstract: Co-doped indium–tin oxide (ITO) films were produced by magnetron sputtering on fused quartz substrates under various conditions. We find that post-growth processing of films affects crucially their electronic and magnetic properties. Films with 30at% of Co show hysteretic magnetization and anomalous Hall effect up to room temperature. Values of up to per Co atom are obtained for the saturation magnetic moment in these films. A mixed magnetic state with Co-rich ITO or Co-metal nanoclusters within a homogeneous ITO:Co matrix might give rise to such behavior. [Copyright &y& Elsevier]

• Interface antiferromagnetic coupling depends on Gd layer in Gd/CoFeTaB multilayer structure. • Interface antiferromagnetic coupling of multilayer structure can be enhanced by annealing. • Interface antiferromagnetic coupling affects magnetic and magnetoresistance properties of the system. By using the magnetron sputtering, a Gd/CoFeTaB multilayer structure film was fabricated, and investigated the effect of annealing temperature on magnetic and magnetoresistance characteristics of the multilayer film. A magnetic compensation phenomenon was observed, which means there is an antiferromagnetic coupling in the Gd/CoFeTaB system. It was found that the annealing enhances the antiferromagnetic coupling, lead to increase the Gilbert damping coefficient. Furthermore, an unsaturated magnetoresistance effect was observed, which is explained by the electron-electron interaction in the system. It is expected that the artificial antiferromagnetic multilayer system with weak macro-magnetism and internal magnetic order will has a good application prospect for the development of spintronics devices. [ABSTRACT FROM AUTHOR]

• Si|CoSi 2 |Sm-Co films with CoSi 2 interfacial layer thickness of 20 and 35 nm were grown. • XRD studies confirmed the crystallization of Sm 2 Co 17 , SmCo 5 and CoSi 2 phases. • Magnetization reversal mechanisms were studied through angular-dependent hysteresis measurements. • Temperature coefficients of remanence (α) and coercivity (β) were determined. • Films with thicker CoSi 2 -layer exhibited better thermal stability: low 'α' and 'β' values (0.35 ± 0.05 & −0.13 ± 0.02%/°C). Magnetic thin films with a layer sequence of Si|CoSi 2 |Sm-Co were grown by direct sputter deposition at elevated temperatures, through interfacial diffusion between Si (1 0 0) substrate and the overlying Sm-Co layer. HR-TEM analysis revealed the occurrence of CoSi 2 -interfacial layer close to the Si-substrate surface, with controllable thicknesses of ~20 and 35 nm at deposition temperatures: 450 and 500 °C, respectively. XRD studies confirmed the crystallization of Sm 2 Co 17 and SmCo 5 magnetic phases accompanied by the other phases such as CoSi 2 and SmCoSi 2 due to the intermixing of Co and Si -atoms at higher deposition temperatures. The measured coercivity values are found to be increased from 8.7 to 11.6 kOe at higher CoSi 2 -layer thickness. The angular-dependent hysteresis measurements demonstrated a distinct isotropic and uniaxial magnetic anisotropy characteristics for the Sm-Co films consisting of 35 and 20-nm thick CoSi 2 interfacial layers, respectively and the associated magnetization reversal mechanisms are discussed using the Stoner-Wohlfarth model. The temperature coefficients of remanence (α) and coercivity (β) were determined from the temperature-dependent hysteresis curves. The Sm-Co films consisting of 35-nm thick CoSi 2 -layer exhibited a better thermal stability with 'α' and 'β' values of 0.35 ± 0.05%/°C and −0.13 ± 0.02%/°C, respectively. The results of present study provide splendid opportunities for exploiting the potential of CoSi 2 as an under layer, for growing the Sm-Co films towards high-temperature applications. [ABSTRACT FROM AUTHOR]

We present magnetometry data for a range of Fe thicknesses grown on GaAs and InAs substrates in order to determine the factors governing the evolution of the magnetic moment of epitaxial Fe grown on a zinc-blende semiconductor. Fe films grown at room temperature by molecular beam epitaxy were characterized structurally and magnetically. The estimated roughness amplitudes were 0.3 ± 0.2 nm for the Fe/GaAs interface and 0.6 ± 0.2 nm for Fe/InAs. We observe a greater reduction of the Fe magnetic moment for films grown on InAs as compared to GaAs, as the Fe films reach a bulk-like moment (within 10% deviation) at a thickness of ∼5.2 nm and ∼2.2 mn, respectively. We conclude that the growth conditions, in particular interface and interdiffusion effects, are the dominant mechanisms influencing the value of the magnetic moment for ultrathin Fe films on GaAs and InAs. [ABSTRACT FROM AUTHOR]

A series of (Ni75 Fe25)x(SiO2 )(1-x) films with different volume fraction x is fabricated by magnetron co-sputtering technique. The structure, magnetic and high frequency properties are investigated systematically by X-ray diffraction, transmission electronic microscopy, vibrating sample magnetometer, resistivity and complex permeability measurements. The results show that the films consist of Ni75 Fe25 magnetic metal particles uniformly embedded in the insulating SiO2 matrix. The (Ni75 Fe25)x(SiO2)(1-x) films exhibit excellent soft magnetic properties in a wide x range from 0.81 to 0.52 with coercivity Hc not exceeding 5 Oe, which is ascribed to the exchange coupling between magnetic particles due to the long exchange length of Ni75 Fe25 alloy. The smallest Hc is 1.1 Oe obtained for the sample of x = 0.81 with high electrical resistivity ρ = 167 μΩ.cm, and the real part μ' of its initial complex permeability keeps constant of 170 below 550 MHz while the imaginary part μ" is less than 26. The rapid increase of μ" at the frequency higher than 600 MHz can be attributed to the ferromagnetic resonance, whose frequency is estimated to be about 2.2 GHz. For the film of x = 0.52, besides the low Hc (∼3 Oe), very high ρ over 1.18x 104 μΩ. cm has been obtained, implying that this film is quite promising for very high frequency application. [ABSTRACT FROM AUTHOR]

Magnetic properties of ultra-thin Fe [ABSTRACT FROM PUBLISHER]