Thickness Dependence Of Magnetic Anisotropy Research Articles

Thickness-dependence of magnetic anisotropy and domain structure in Ni thin films grown on a PMN-PT substrate

High-quality Ni ferromagnetic thin films with the thicknesses of 180, 240, 330, and 510 nm ± 5 nm were grown on (001)Pb(Mg1/3Nb2/3)0.7Ti0.3O3 (PMN-PT) single-crystal substrates by magnetron sputtering followed by annealing. The thickness dependence of magnetic anisotropy was investigated using ferromagnetic resonance, indicating that the 180 nm Ni thin film exhibits a large magnetic anisotropy field. Increasing the film’s thickness resulted in a reduction of the magnetic anisotropy. Well-defined stripe domain structures in Ni thin films were observed. Calculations based on the tilted partial flux closure domain structure with Bloch wall and Neel wall indicate an increase in the primary domain size and closure domain size of Ni thin films with increasing film thickness.

Thickness dependence of magnetic anisotropy and intrinsic anomalous Hall effect in epitaxial Co2MnAl film

We have investigated the thickness dependence of magnetic anisotropy and intrinsic anomalous Hall effect (AHE) in single-crystalline full-Heusler alloy Co2MnAl (CMA) grown by molecular-beam epitaxy on GaAs(001). The magnetic anisotropy is the interplay of uniaxial and the fourfold anisotropy, and the corresponding anisotropy constants have been deduced. Considering the thickness of CMA is small, we ascribe it to the influence from interface stress. The AHE in CMA is found to be well described by a proper scaling. The intrinsic anomalous conductivity is found to be smaller than the calculated one and is thickness dependent, which is ascribed to the influence of chemical ordering by affecting the band structure and Fermi surface.

Thickness dependence of magnetic anisotropy and domains in amorphous Co40Fe40B20 thin films grown on PET flexible substrates

The amorphous Co40Fe40B20 (CoFeB) films (5–200nm in thickness) were grown on flexible polyethylene terephthalate (PET) substrates using the DC magnetron-sputtering method. The thickness dependence of structural and magnetic properties of flexible CoFeB thin films was investigated in detail. The in-plane uniaxial magnetic anisotropy induced by strain as a function of thickness was obtained in flexible CoFeB thin films, and a critical thickness of ~150nm for in-plane magnetic anisotropy was observed. Moreover, the domains and the uniaxial anisotropy as a function of angular direction of applied magnetic field were characterized. The results show potential for designing CoFeB-based flexible spintronic devices in which the physical parameters could be tailored by controlling the thickness of the thin film.

Effect of GaAs (100) substrate surface reconstruction on magnetic properties of Ni thin films

Abstract Effects of (4×6) and (2×4) reconstructed surfaces of GaAs (100) substrate on magnetic properties have been investigated for nickel thin films by using ferromagnetic resonance technique. The films were grown by molecular beam epitaxy in ultrahigh vacuum condition, with 20–40 nm thickness range. X-ray diffraction measurements showed that all films have a single crystalline structure. In the film plane the nickel films exhibited a combination of two fold and four fold anisotropy induced by unsatisfied tetrahedral bonds of Ga and As rows oriented along [ 110 ] and [ 1 1 ¯ 0 ] directions. Effects of different reconstructions on magnetic anisotropies were discovered to be more dominant in the film normal. The physical mechanisms responsible for the observed surface reconstruction and thickness dependence of magnetic anisotropy are discussed in detail.

Magnetization Angle and Thickness Dependence of Perpendicular Exchange Anisotropy in [Pd/Co]n/FeMn Films

The magnetization angle and thickness dependence of magnetic anisotropy in the exchange-biased [Pd/Co]×5/FeMn multilayers with an out-of-plane anisotropy were investigated to determine the origin of perpendicular exchange biasing. As the Co thickness increased to 1.5 ㎚ in the [Pd(0.8 ㎚)/Co(t)]×5/FeMn(120 ㎚) films, the hysteresis loops were converted from square loops at a thin Co (＜0.4 ㎚) to complicated round ones at a thick Co. The irregularly asymmetric step (IAS) at the left top of the loop appeared in the loop of the 0.6-㎚ Co film due to an inhomogeneity in the exchange anisotropy. As the Pd thickness increased to 1.6 ㎚, the step disappeared, and the perpendicular magnetic anisotropy was maximized in the Co thickness between 0.6 and 0.9 ㎚. The conversion of the magnetization loop along the magnetization angle coincided with the equation H (eff) = Ho cos θ. The IAS of the 0.8-㎚ Pd film disappeared after thermal annealing up to 200℃ under an external magnetic field.

Thickness dependence of magnetic anisotropy in uncovered and Cu-covered Fe∕GaAs(110) ultrathin films studied by in situ Brillouin light scattering

The thickness dependence of magnetic anisotropy in Fe∕GaAs(110) ultrathin films has been investigated by in situ Brillouin light scattering. A simultaneous best-fit analysis of the spin-wave frequency, measured as a function of (i) the intensity of the applied magnetic field, (ii) its direction in the film plane, and (iii) the incidence angle of light, enabled us to determine several magnetic parameters, including the film thickness, and both the in-plane and out-of-plane magnetic anisotropy constants. A marked evolution of the strength as well as of the symmetry of the in-plane magnetic anisotropy has been observed for increasing thickness. The effect of a nonmagnetic Cu capping layer on the magnetic properties of the Fe films has also been studied.

Thickness dependence of magnetic anisotropy in thin Ni films electrodeposited onto the (011) and (001) surfaces of n-GaAs

Brillouin light scattering from thermal spin waves has been exploited to investigate the thickness dependence of magnetic anisotropy of Ni films, with thickness in the range 7–35nm, grown by electrodeposition onto either (011)- or (001)-GaAs substrates. In the former case, Ni films exhibit a well-defined in-plane uniaxial anisotropy induced by the symmetry of the substrate. In the case of the (001)-GaAs substrate, instead, the magnetic anisotropy results from a combination of both a fourfold and a twofold contribution. The physical mechanisms responsible for the observed anisotropy, as well as its dependence on film thickness, are discussed in detail.

Thickness dependence of magnetic anisotropy in ultrathin Co/GaAs(0 0 1) films

Brillouin light scattering has been exploited in situ to study spin waves in ultrathin Co/GaAs(0 0 1) films of different thickness in the range between 1 and 7 nm, i.e. both before and after the bcc–hcp phase transition. A marked evolution of the in-plane anisotropy has been observed in connection with the structural transformation. Measurements of the spin-wave frequency as a function of the in-plane direction and of the intensity of the applied magnetic field, as well as of the incidence angle of light, enabled us to determine the magnetic parameters of the films, including the in-plane anisotropy constants.

In situBrillouin scattering study of the thickness dependence of magnetic anisotropy in uncovered and Cu-covered Fe/GaAs(100) ultrathin films

The dynamical magnetic properties of ultrathin Fe/GaAs(001) films in the thickness range 5--100 \AA{} have been studied by in situ Brillouin light scattering. Measurement of the spin-wave frequency as a function of both the intensity and the in-plane direction of the applied magnetic field, as well as of the incidence angle of light, enabled us to determine the magnetic parameters of the films. A continuous evolution from uniaxial to biaxial in-plane magnetic anisotropy has been observed with increasing thickness, together with a marked increase of the effective magnetization. Remarkably, we also found that the presence of a Cu capping layer, even 1 ML thick, completely suppresses the uniaxial anisotropy in the thinnest samples. This effect is discussed in terms of the possible underlying physical mechanisms.

Magnetic Anisotropy in Eus-pbs Multilayers

We present the results of ferromagnetic resonance studies of the thickness dependence of magnetic anisotropy in 2 series of EuS-PbS multilayers grown on (111) BaF2 and (100) KCl substrates with the EuS thickness varying in the range d = 6-70 A. The anisotropy constant K was found to follow the dependence K(d) = Kv + 2Ks/d, with the surface term Ks larger for layers grown on BaF2 as compared to KCl. This difference is discussed in terms of different thermal stress-induced distortions of cubic crystal lattice of EuS. We found that the thickness of EuS layer required for the perpendicular (to the layer) magnetization is d = 2-3 A, i.e., it is below 1 monolayer.

Magnetic anisotropy of epitaxial Au/Co/Ag and Ag/Co/Au superlattices

RHEED observations and the Co layer thickness dependence of magnetic anisotropy in Au/Co/Ag, Ag/Co/Au superlattices indicate that the nature of Au/Co interfaces depends on the sequence of deposition and that the magnetoelastic anisotropy contributing to the perpendicular magnetic anisotropy originates only from the Co interface regions deposited onto Au layers.