Dependence of the SWR Linewidth on the Wavevector in Amorphous Thin Films

Work supported in part by the Central Research Project 01.08.B.Zadanie pt. „Digitalizacja i udostępnienie w Cyfrowym Repozytorium Uniwersytetu Łódzkiego kolekcji czasopism naukowych wydawanych przez Uniwersytet Łódzki” nr 885/P-DUN/2014 zostało dofinansowane ze środków MNiSW w ramach działalności upowszechniającej naukę

Temperature dependences of surface magnetoelastic constants of ultrathin Fe/GaAs (001) films

The magnetoelastic constants of epitaxial iron films prepared by dc magnetron sputtering on single crystal GaAs (001) substrate in argon atmosphere and covered with a protective Si layer have been investigated in the temperature range 10–300 K by means of the strain modulated ferromagnetic resonance. It has been shown that the magnetoelastic constants strongly depend on the thickness of the film. The surface components of the magnetoelastic constants have been determined and analyzed within the Néel and dipolar models. The proposed analysis of experimental data gives chance for deeper insight into mechanisms responsible for magnetostriction of iron thin films

Interval Computations of Ferromagnetic Resonance Conditions in Exchange-Biased Bilayers

The main purpose of this paper is to promote the use of interval calculus in physics. As an example we use the system consisting of two thin films, one ferromagnetic and another one antiferromagnetic, deposited one atop of the other. We successfully and accurately simulate the positions of resonance fields of such a system, as seen in ferromagnetic resonance experiment. Interval calculations have revealed the presence of 1, 2 and sometimes even 4 distinct equilibrium configurations of the system, all corresponding to the same resonance field, when the field has a component antiparallel to that of cooling field, while only 1 such position when it points in the opposite direction. In both cases only a single resonance line is observed. As an added value we show that the exchange-biased system is in the metastable state, out of true thermodynamical equilibrium

Surface Magnetostriction

Experimental and theoretical research on magnetostriction of nanoscale magnetic multilayers is reviewed. The importance of interfaces and the occurrence of the surface magnetostriction is emphasized. It is shown that the dependence of magnetostriction on the magnetic layer thickness is due to the magnetostrictive strains localized at the interface

Surface Magnetostriction within Néel's Model

The aim of the present paper is to determine the surface magnetostriction in the spirit of Néel's model of the surface magnetic anisotropy. Calculations have been performed for bcc and fcc ferromagnetic crystals

Magnetic Anisotropy and Magnetostriction Oscillations in Magnetic Multilayers

Interlayer pseudodipolar coupling between two ferromagnets separated by nonmagnetic spacer is analyzed. It was shown that this type of interaction should induce magnetic anisotropy and magnetostriction oscillations. It was also predicted that both magnetic anisotropy and magnetostriction decrease with an increase in the spacer thickness. This effect was observed in [permalloy/Cu]$\text{}_{100}$ multilayers

Dipolar Contributions to Magnetoelastic Energy of Crystal Grains with Interfaces

The magnetic anisotropy and magnetostriction in nanocrystalline grains in non-magnetic or magnetic matrix (nanoparticles or nanocrystalline materials) differ from their bulk properties. The interactions between atoms at the interface play the important role in these magnetic properties. In this paper the magnetic dipolar contribution to magnetostriction energy has been calculated for spherical crystal grains (of bcc and fcc symmetry) with interface layer of atoms possessing different magnetic moment. Total magnetoelastic energy of the sphere-interface system is a sum of magnetoelastic energy of the sphere, energy of the interactions between the sphere and the interface and also the energy of the interface. It was shown that magnetoelastic energy depends on the sphere size and interface thickness

MAGNETOSTRICTION CONSTANT OF MULTILAYER Ni-Ag FILMS DETERMINED BY FERROMAGNETIC RESONANCE

The results of magnetostriction constant λs, of multilayer Ni-Ag films are reported. The measurements have been performed at room temperature using strain modulated ferromagnetic resonance method. The magnetostriction constant λs depends linearly on the inverse Ni layer thickness. This effect is suggested to be due to the reduced local symmetry in interfaces

Dependence of the SWR Linewidth on the Wavevector in Amorphous Thin Films

Work supported in part by the Central Research Project 01.08.B

Correlation between linear magnetostriction and magnetocaloric effect in the Fe7Se8 single crystals

The effect of the change in size under the influence of an applied magnetic field (magnetostriction) was studied in Fe _7 Se _8 single crystals. It was shown that a systematic change in the unit-cell constants, induced by an external magnetic field and dependent on the direction and magnitude of this field, strongly correlates with the change in the spin reorientation temperature ( T _SRT ) and the magnetic entropy change, which is strongly dependent on T _SRT and magnetization. The obtained results suggest that the relation between magnetostriction and the change in magnetic entropy (Δ S _m ), reported previously for different materials, seems to have universal character, and magnetostriction can be used as an indirect method to estimate the change in magnetic entropy in Fe _7 Se _8 single crystals substituted with transition metals