Magnetocrystalline Anisotropy K1 Research Articles

Magnetic anisotropy and reversal in epitaxial FeGa/IrMn bilayers with different orientations of exchange bias

Epitaxial FeGa/IrMn bilayers with exchange biases along the FeGa[100] and [110] directions are prepared on MgO(001) single crystal substrates by magnetron sputtering through controlling the orientation of the external field <i>in situ</i> applied during growth. The effect of the exchange bias orientation on the magnetic switching process and the magnetic switching field are studied. The X-ray <i>φ</i>-scan indicates that the FeGa layer is epitaxially grown with a 45° in-plane rotation on the MgO(001) substrate along the FeGa(001)[110] direction and the MgO(001)[100] direction. The measurements of the angular dependence of the ferromagnetic resonance field and the corresponding fitting to the Kittel equation show that the samples have a superposition of fourfold symmetric magnetocrystalline anisotropy <inline-formula><tex-math id="M4">\begin{document}$ {K}_{1} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="12-20220166_M4.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="12-20220166_M4.png"/></alternatives></inline-formula>, unidirectional magnetic exchange bias anisotropy <inline-formula><tex-math id="M5">\begin{document}$ {K}_{\mathrm{e}\mathrm{b}} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="12-20220166_M5.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="12-20220166_M5.png"/></alternatives></inline-formula>, and uniaxial magnetic anisotropy <inline-formula><tex-math id="M6">\begin{document}$ {K}_{\mathrm{u}} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="12-20220166_M6.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="12-20220166_M6.png"/></alternatives></inline-formula> with configuration of <inline-formula><tex-math id="M7">\begin{document}$ {K}_{\mathrm{e}\mathrm{b}}//\left[100\right] $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="12-20220166_M7.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="12-20220166_M7.png"/></alternatives></inline-formula> or <inline-formula><tex-math id="M8">\begin{document}$ {K}_{\mathrm{e}\mathrm{b}}//\left[110\right] $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="12-20220166_M8.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="12-20220166_M8.png"/></alternatives></inline-formula>. The combined longitudinal and transverse magneto-optical Kerr effect measurements show that sample with <inline-formula><tex-math id="M9">\begin{document}$ {K}_{\mathrm{e}\mathrm{b}}//\left[100\right] $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="12-20220166_M9.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="12-20220166_M9.png"/></alternatives></inline-formula> exhibits square loops, asymmetrically shaped loops, and one-sided two-step loops in different external magnetic field directions. In contrast, the sample with <inline-formula><tex-math id="M10">\begin{document}$ {K}_{\mathrm{e}\mathrm{b}}//\left[110\right] $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="12-20220166_M10.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="12-20220166_M10.png"/></alternatives></inline-formula> exhibits one-sided two-step and two-sided two-step loops as the magnetic field orientation changes. Because the <inline-formula><tex-math id="M11">\begin{document}$ {K}_{1} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="12-20220166_M11.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="12-20220166_M11.png"/></alternatives></inline-formula> is superimposed by <inline-formula><tex-math id="M12">\begin{document}$ {K}_{\mathrm{u}} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="12-20220166_M12.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="12-20220166_M12.png"/></alternatives></inline-formula> and <inline-formula><tex-math id="M13">\begin{document}$ {K}_{\mathrm{e}\mathrm{b}} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="12-20220166_M13.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="12-20220166_M13.png"/></alternatives></inline-formula>, the in-plane fourfold symmetry of the magnetic anisotropy energy is broken. The local minima are no longer strictly along the in-plane <inline-formula><tex-math id="M14">\begin{document}$ \left\langle{100}\right\rangle $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="12-20220166_M14.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="12-20220166_M14.png"/></alternatives></inline-formula> directions, but make a deviation angle which depends on the relative orientation and strength of magnetic anisotropy. A model based on the domain wall nucleation and propagation is proposed with considering the different orientations of <inline-formula><tex-math id="M15">\begin{document}$ {K}_{\mathrm{e}\mathrm{b}} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="12-20220166_M15.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="12-20220166_M15.png"/></alternatives></inline-formula>, which can nicely explain the change of the magnetic switching route with the magnetic field orientation and fit the angular dependence of the magnetic switching fields, indicating a significant change of domain wall nucleation energy as the orientation of <inline-formula><tex-math id="M16">\begin{document}$ {K}_{\mathrm{e}\mathrm{b}} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="12-20220166_M16.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="12-20220166_M16.png"/></alternatives></inline-formula> changes.

Intrinsic Magnetic Properties of a Highly Anisotropic Rare‐Earth‐Free Fe2P‐Based Magnet

AbstractPermanent magnets are applied in many large‐scale and emerging applications and are crucial components in numerous established and newly evolving technologies. Rare‐earth magnets exhibit excellent hard magnetic properties; however, their applications are limited by the price and supply risk of the strategic rare‐earth elements. Therefore, there is an increasing demand for inexpensive magnets without strategic elements. Here, the authors report the intrinsic highly‐anisotropic magnetic properties of Co and Si co‐doped single crystals (Fe1−yCoy)2P1−xSix (y ≈ 0.09). Co increases Curie temperature TC; Si doping decreases magnetocrystalline anisotropy K1 and also increases TC significantly because of the enhanced interlayer interaction. The maximum room temperature magnetocrystalline anisotropy K1 = 1.09 MJ m−3 is achieved for x = 0.22, with saturation magnetization µ0Ms = 0.96 T and TC = 506 K. The theoretical maximum energy product is one of the largest for any magnet without a rare earth or Pt. Besides its promising intrinsic magnetic properties and absence of any strategic elements, other advantages are phase stability at high temperatures and excellent corrosion resistance, which make this material most promising for permanent magnetic development that will have a positive influence in industry and daily life.

Formation mechanism and energy interaction of spontaneous skyrmion in nanodisks

Topological spin textures, such as magnetic skyrmion, have great promises in data storage applications due to their inherent stability. Contrary to the general idea, simulation results here indicate that spontaneous skyrmion equilibrium states can exist generally in certain materials without the assistance of Dzyaloshinskii-Moriya interaction, external fields or defects. The spin configurations are closely related to the variations of the magnetocrystalline anisotropy K1, exchange interaction A, and saturation magnetization MS. The system with low anisotropy is conducive to the formation of vortex, while a single domain can be formed in the large range of K1 and A in the system with small MS. Landau-Lifshitz-Gilbert equation is used to investigate the variations of different interaction energies in the formation of topological domains. In the range where skyrmions are formed, the anisotropic energy, exchange energy and demagnetization energy account for 40 ~ 80%, 10 ~ 20%, 10 ~ 40% of the total energy. Meanwhile, a phase diagram of equilibrium magnetic moment distribution under different intrinsic properties is obtained. The K1, A and MS values of skyrmions range from 1.6 ~ 2.5 × 105 J/m3, 1.6 ~ 6.8 × 10-12 J/m, and 7.1 ~ 8.8 × 105 A/m in this simulation. By adjusting the material parameters, various competing interactions in magnetic nanostructures can be controlled to form skyrmion textures, which provide important insights for understanding the formation mechanism of nontrivial topological domains.

Effect of Ar+ beam sputtering on the magnetic anisotropy of Fe thin films deposited on the MgO(0 0 1) substrate

The Fe thin films with different initial thickness were prepared on MgO(001) substrate. Ar+ ion beam having energy of 3keV was used to sputter the film at incident angle of 80° with respect to the film normal. Low energy electron diffraction (LEED) was employed to study the morphology and crystal quality of the film. Moreover surface magneto-optical Kerr effect (SMOKE) and anisotropic magnetoresistance (AMR) setups were used to investigate the magnetic properties of the Fe film. The values of magnetocrystalline anisotropy K1 and induced in-plane uniaxial magnetic anisotropy (UMA) Ku were derived from torque curves on the base of AMR results and found that the value of Ku was increasing with increasing the sputtering time while the intrinsic magnetocrystalline anisotropy K1 was not affected by sputtering. Similarly it is observed that the value of K1 increases with the thickness. We noted that ion beam sputtering can be used as an effective technique of manipulating the magnetic anisotropy of ultrathin magnetic films.

Effect of band filling on anomalous Hall conductivity and magneto-crystalline anisotropy in NiFe epitaxial thin films

The anomalous Hall effect (AHE) and magneto-crystalline anisotropy (MCA) are investigated in epitaxial NixFe1−x thin films grown on MgO (001) substrates. The scattering independent term b of anomalous Hall conductivity shows obvious correlation with cubic magneto-crystalline anisotropy K1. When nickel content x decreasing, both b and K1 vary continuously from negative to positive, changing sign at about x = 0.85. Ab initio calculations indicate NixFe1−x has more abundant band structures than pure Ni due to the tuning of valence electrons (band fillings), resulting in the increased b and K1. This remarkable correlation between b and K1 can be attributed to the effect of band filling near the Fermi surface.

Site occupancy and magnetic properties of Al-substituted M-type strontium hexaferrite

We use first-principles total-energy calculations based on density functional theory to study the site occupancy and magnetic properties of Al-substituted M-type strontium hexaferrite SrFe12−xAlxO19 with x = 0.5 and x = 1.0. We find that the non-magnetic Al3+ ions preferentially replace Fe3+ ions at two of the majority spin sites, 2a and 12k, eliminating their positive contribution to the total magnetization causing the saturation magnetization Ms to be reduced as Al concentration x is increased. Our formation probability analysis further provides the explanation for increased magnetic anisotropy field when the fraction of Al is increased. Although Al3+ ions preferentially occupy the 2a sites at a low temperature, the occupation probability of the 12k site increases with the rise of the temperature. At a typical annealing temperature (>700 °C) Al3+ ions are much more likely to occupy the 12k site than the 2a site. Although this causes the magnetocrystalline anisotropy K1 to be reduced slightly, the reduction in Ms is much more significant. Their combined effect causes the anisotropy field Ha to increase as the fraction of Al is increased, consistent with recent experimental measurements.

Microstructural Change and Magnetic Properties of Nanocrystalline Fe-Si-B-Nb-Cu Based Alloys Containing Minor Elements

The effect of minor element additions (Ca, Al) on microstructural change and magnetic properties of Fe-Nb-Cu-Si-B alloy has been investigated, in this paper. The Fe-Si-B-Nb-Cu(-Ca-Al) alloys were prepared by arc melting in argon gas atmosphere. The alloy ribbons were fabricated by melt-spinning, and heat-treated under a nitrogen atmosphere at 520-570oC for 1 h. The soft magnetic properties of the ribbon core were analyzed using the AC B-H meter. A differential scanning calorimetry (DSC) was used to examine the crystallization behavior of the amorphous alloy ribbon. The microstructure was observed by X-ray diffraction (XRD), transmission electron microscope (TEM) and scanning electron microscope (SEM). The addition of Ca increased the electrical resistivity to reduce the eddy current loss. And the addition of Al decreased the intrinsic magnetocrystalline anisotropy K1 resulting in the increased permeability. The reduction in the size of the α-Fe precipitates was observed in the alloys containing of Ca and Al. Based on the results, it can be concluded that the additions of Ca and Al notably improved the soft magnetic properties such as permeability, coercivity and core loss in the Fe-Nb-Cu-Si-B base nanocrystalline alloys.

Upper Limit for the Coercive Force in NdFeB and PrFeB Magnets

Hysteresis loops were calculated according the Stoner-Wohlfarth model. Using as values for constants of magnetocrystalline anisotropy K1 =4.5 and K2=0.66 (J m−3), and 1.61 T for magnetization of saturation of Nd2Fe14B, the maximum coercivity for isotropic Nd2Fe14B was predicted as mi0 H = 2.95 T (29.5kOe). For a very well aligned magnet, with Mr/Ms=0.96, following the f (alpha)=cosn(alpha) distribution, the theoretical coercivity limit was estimated as mi0 H = 3.6 T (36 kOe). These estimates are valid for the ternary Nd2Fe14B alloy. It is predicted the upper limit for the coercive field as function of grain size for NdFeB and PrFeB magnets. Addition of Praseodymium is an effective method for increasing coercivity of NdFeB magnets.

Assembly of uniaxially aligned rare-earth-free nanomagnets

We report HfCo7 nanoparticles with appreciable permanent-magnet properties (magnetocrystalline anisotropy K1 ≈ 10 Mergs/cm3, coercivity Hc ≈ 4.4 kOe, and magnetic polarization Js ≈ 10.9 kG at 300 K) deposited by a single-step cluster-deposition method. The direct crystalline-ordering of nanoparticles during the gas-aggregation process, without the requirement of a high-temperature thermal annealing, provides an unique opportunity to align their easy axes uniaxially by applying a magnetic field of about 5 kOe prior to deposition, and subsequently to fabricate exchange-coupled nanocomposites having Js as high as 16.6 kG by co-depositing soft magnetic Fe-Co. This study suggests HfCo7 as a promising rare-earth-free permanent-magnet alloy, which is important for mitigating the critical-materials aspects of rare-earth elements.

Structural and Magnetic Properties of Nanosized Barium Hexaferrite Powders Obtained by Microemulsion Technique

Thin hexagonal barium hexaferrite particles synthesized using the microemulsion technique were studied. A water-in-oil reverse microemulsion system with cetyltrimethylammonium bromide (CTAB) as a cationic surfactant, n-butanol as a co-surfactant, n-hexanol as a continuous oil phase, and an aqueous phase were used. The microstructural and magnetic properties were investigated. The particles obtained were mono-domain with average particle size 280 nm. The magnetic properties of the powder were investigated at 4.2 K and at room temperature. The saturation magnetization was 48.86 emu/g and the coercivity, 2.4 x 105 A/m at room temperature. The anisotropy field Ha and magneto-crystalline anisotropy K1 were 1.4 x 106 A/m and 2.37 x 105 J/m3, respectively.

Mn–Zn ferrites for magnetic sensor in space applications

We describe the optimization of Mn–Zn ferrites having a high permeability between −50 and +150°C. These ferrites are intended to be integrated into a magnetic field sensor for space mission. The chemical composition Mnx2+Zny2+Fe0.052+Ti0.014+Fe23+O4 was investigated by varying the Mn∕Zn ratio. The magnetic characterizations revealed that the initial permeability was increased for high Zn content while the Curie temperature was decreased. A local maximum of the permeability was observed at a specific temperature meaning, the magnetocrystalline anisotropy K1 became zero. The temperature T0 at which K1 was canceled (compensation temperature) depends on the chemical composition just like the Curie temperature TC: the higher the zinc content, the lower T0 and TC. The best compromise was obtained for a ferrite formulation with a Mn∕Zn ratio around 1.8 and with a small titanium oxide addition. Permeability higher than 2400 was obtained between −50 and +150°C and up to 500kHz. The use of ferrite core with the best formulation and shape will allow to measure magnetic field as low as 50fT∕√Hz on a wide frequency range, from 300Hz up to 200kHz.

Structure-induced magnetic anisotropy in the Fe(110)∕Mo(110)∕Al2O3(112¯0) system

Fe(110) films were epitaxially grown on sapphire substrates using a Mo(110) buffer layer in an ultrahigh-vacuum molecular-beam epitaxy system. The magnetic properties were examined ex situ by Brillouin light scattering and superconducting quantum interference device magnetometry. To determine the magnetic anisotropy constants the frequency of the Damon-Eshbach [J. Phys. Chem. Solids 19, 308 (1961)] surface spin-wave mode was measured as a function of the in-plane angle between the external magnetic field and the Fe[001] crystal axis. The angle-dependent frequency was fitted by a spin-wave model. We found that the easy axis of the cubic magnetocrystalline anisotropy K1 and an additional uniaxial in-plane anisotropy K‖(2) are aligned parallel to the in-plane Fe[001] axis for Fe-layer thicknesses from 0.8to37nm, with K1 increasing and K‖(2) decreasing with increasing Fe thickness. Possible origins of the observed uniaxial anisotropy are discussed.

Modelling of magneto‐mechanical hysteresis loops in Ni‐Mn‐Ga shape memory alloys

A predictive model of field-induced strain in Ni-Mn-Ga ferromagnetic shape memory alloys is proposed. In this study, magnetocrystalline anisotropy K1 is introduced to permit magnetisation rotation in martensite platelets. The demagnetisation field induced by the shape of platelets is investigated. The proposed model is identified on experiments performed by Straka et al. This identification shows that observed macroscopic hysteresis loops, i.e. magnetisation and detwinning strain versus applied magnetic field, correspond exactly to a successive activation of three mechanisms: Movement of 180° domain walls, rotation of magnetisation and martensite detwinning. As expected, magnetization and strain -induced by magnetic field- in a single crystal are mainly given by the mobility of twin boundaries and magnetic anisotropies (due to the martensite crystallographic structure and to the shape of platelets). (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

High-temperature AC magnetic properties of FeCo-based soft magnets

The temperature dependence of AC magnetic properties of soft magnetic Co27Cr0.6Ni0.6Febal alloys has been studied. Microstructural characterization indicates that the alloy has a disordered BCC structure which is insensitive to heat-treatment. At low frequencies, the alloy shows a low coercivity Hc, high saturation magnetization Ms, and high magnetic permeability μm. As the frequency increases, all those properties deteriorate due to the damping of magnetic domain walls. On the other hand, Hc and Ms decrease, and μm increases with increasing temperature in the range of 20–600oC. The change of Hc and μm with temperature is attributed to the variation of magnetocrystalline anisotropy K1, which also improves the core loss at high temperature.

Magnetic domain structures of 1:12 type nitrides NdFe10.5Mo1.5N x

The magnetic domain structures of the 1:12 type alloy NdFe10.5Mo1.5 and its nitride were firstly investigated by using magnetic force microscope (MFM). A complicated corrugation and spike magnetic domain structure was observed in NdFe10.5Mo1.5alloy. Upon nitrogenation, a stripe domain structure occurs due to the dramatic increase of the uniaxial magneto-crystalline anisotropy K1 induced by nitrogenation. Based on the basic domain theories, the origin of these domain patterns was analyzed and the reason of domain structure transition is explained quantitatively. The domain wall energy γ, exchange constant A and single-domain particle size Dc of NdFe10.5 Mo1.5 and NdFe10.5-Mo1.5N x were calculated in combination with the measured domain width ω and magnetic parameters. A comparison of magnetic parameters with those of SmCo5 and Nd2Fe14B permanent materials was also made.

電源用Ｍｎ‐Ｚｎフェライトの渦電流損失解析

An attempt was made to divide power loss. PB, in Mn-Zn ferrites into hysteresis loss. Ph, eddy current loss, and residualloss factors experimentally. The temperature, Tmin, at which Ph exhibits minimum value coincides with secondary peak temperature of initial permeability. so that magnetocrystalline anisotropy K1 becomes null at Tmin, The relationship between (PB-Ph) and electrical resistivity. ρ, was analyzed, assuming that every sample has similar magnetic domain structure at K1= 0. It was found that (PB-Ph) shows linear dependence on 1/ρ at Tmin and each loss factor can be obtained from (PB-Ph) vs. 1/ρ plot. The gradient of the line in (PB-Ph) vs. 1/ρ plot, which is proportional to f2 · B2m, was identified as the eddy current loss. The residual loss was obtained from (PB-Ph) at ρ→∞ in the plots.

Ｃｏ‐Ｎｉ‐Ｆｅ三元合金における単結晶の結晶磁気異方性および蒸着膜の磁気特性

The magnetocrystalline anisotropy of fcc Co-Ni-Fe ternary alloys with Co content of more than 40% was determined at room temperature. The easy axis of magnetization was the direction and sign of K1 was negative for all the samples. The magnitude of magnetocrystalline anisotropy K1 increased with an increase in the Co composition. The values of K1 were -0.2 × 105 erg/cm3 for Co40Fe40Ni20, and -7.1 × 105 erg/cm3 for Co80Ni5Fe15, which are near the zero magnetostriction line. The magnetic properties of films evaporated on glass substrate were also studied in the same composition range.

Effects of Al on the magnetic properties of nanocrystalline Fe73.5Cu1Nb3Si13.5B9 alloys

The effects of Al on the soft magnetic properties of nanocrystalline Fe73.5−xAlxCu1Nb3Si13.5B9 alloy ribbons are investigated in the composition range of 0≤x≤1.0. The relative initial permeability at 1 kHz is found to increase by the addition of Al, and reaches the peak value at x=0.1. The coercivity decreases, rather significantly, with the Al content in the whole composition range investigated in the present work, the values of the coercivity being 12.5 mOe at x=0 and 9.3 mOe at x=1.0. The magnetic induction at an applied field of 10 Oe, however, decreases moderately by the introduction of Al, possibly due to the dilution effect. The improvement in the soft magnetic properties is considered to result from the reduction in the grain size of the α Fe-Si solid solution phase of the Al-added alloy ribbons, which has been observed by transmission electron microscopy. Another factor may be due to the decrease in the intrinsic magnetocrystalline anisotropy K1 as Al is added to the alloy.

Stable single-domain to superparamagnetic transition during low-temperature oxidation of oceanic basalts

Recent experimental data on synthetic titanomaghemites indicate that oxidation is accompanied by a decrease in magnetocrystalline anisotropy K1 as well as a decrease in the saturation magnetization σs. Theory of relaxation times predicts that the decrease of σs and K1 with oxidation will cause single-domain titanomagnetite grains with initially low blocking temperatures to become superparamagnetic as they are oxidized to titanomaghemite. For titanomagnetites (Fe3−x TixO4) of composition x = 0.4 and x = 0.5 the affected blocking temperature range is approximately 200° and 125°K below the Curie point, respectively. However, for x = 0.6 titanomagnetites the blocking temperature range affected is within 80°K of the Curie point and spans a temperature interval from 325° to as high as 380°K, depending on the degree of oxidation. The rapid quenching of oceanic pillow lavas (average composition x ≅ 0.6) produces efficient thermoremanence carriers but will also result in a significant grain size and blocking temperature distribution. Thus low-temperature oxidation of oceanic basalts could cause a significant portion of the originally stable carriers of natural remanence to become superparamagnetic. This mechanism could aid in explaining the large natural remanent magnetization intensity decrease of dredged basalts with distance from the mid-Atlantic ridge.

Origin of the Periodic Component of Anisotropy Dispersion in Ni-Fe Films II

The periodic component of the angular dispersion α90 was measured on Ni-Fe films of various compositions deposited onto glass substrates kept at different temperatures. When the substrate temperature ts is about 300°C, the films are almost free from the stress and thus the angular dispersion α90 comes mainly from the magneto-crystalline anisotropy K1 of the crystallites. However, if ts is far below 300°C, then α90 comes not only from K1 but also from the magneto-elastic anisotropy Kσ, α90∝(K12+Kσ2)1/2/Ku, where Ku is the uniaxial anisotropy constant of the film. The anisotropic part of the stress σa estimated from α90 depends on the substrate temperature as σa∼(300-ts)×107(dyn/cm2).