MAGNETO-OPTIC PROPERTIES OF AMORPHOUS NixY1-x FILMS (original) (raw)

Surface induced magnetic and magneto-optical properties in amorphous CoxY1−x thin films

Journal of Magnetism and Magnetic Materials, 1988

Room temperature magneto-optical spectroscopy (transverse Kerr effect) (MOKE) and transverse biased initial susceptibility (TBIS) measurements have been carried out in amorphous Co~,Y1_ x thin films (thickness: 1000 ~,). The chemical composition range studied was 0.50 ~< x ~< 0.80. The MOKE, TBIS and coercive force show a marked dependence on x. For x > 0.65 the MOKE parameter 8 k is positive and TBIS behaviour leads to a magnetization ripple contribution to the effective field. When x < 0.60, 8 k is negative and TBIS behaviour may be explained by a cluster model of non-interacting magnetically ordered regions and ,'andom distribution of associated anisotropies. At x = 0.65, two magnetic phases become apparent from MOKE a TBIS beh:'.viour. These facts are explained by the occurrence of sublayer Co-enriched regions induced by surface segregation of Y. Optical effects in protective Y-oxide layers may be at the origin of the change in Kerr effect polarity.

Hall effect and resistivity in Y-3d (Fe, Ni) based amorphous films

Journal of Applied Physics, 1993

We have studied the magnetic behavior of amorphous Y-3d based systems, using resistivity and Hall effect measurements. Y,Ni,-, metallic glasses show a very different magnetic behavior from Fe glasses, with a cross over (x=0.22) from weak itinerant ferromagnetism to paramagnetism. Two more magnetic metallic glasses have been studied, a typical ferromagnetic system Fe-SLY (with Fe content only 52%) and a noncollinear ferrimagnetic (sperimagnetic) system (Fe-Si-Tb). In spite of their very different magnetic mechanisms the resistivities ali show low temperature minima with logarithmic dependence below the minima temperatures. This behavior is not magnetic field dependent, with applied fields up to 70 kOe. We show Hall effect measurements that easily distinguish the different intrinsic mechanisms.

Magnetoresistive properties of Ni-based thick films

Journal of Materials Science: Materials in Electronics, 1990

Investigations have been carried out on the electrical properties of nickel-based films prepared from air-fireable pastes on alumina substrates. In particular, magnetoresistive effects have been studied as a function of temperature, strength and direction of the magnetic field. These properties were determined in films at different stages of formation, i.e. prepared at various peak firing temperatures and dwell times, and compared with those displayed by nickel foils. These results provide the basis for the development of magnetoresistive thick-film sensors.

Surface anisotropy energy of thin amorphous magnetic films of (Gd1−xCox)1−yMoy alloys; experimental results

Journal of Magnetism and Magnetic Materials, 1985

Surface excitations in thin amorphous (Gdl_xCOx)l_yMOy films obtained by the rf sputtering technique were studied. A microwave spectrometer at X-band was used for magnetic resonance investigation with external magnetic field rotating from perpendicular to parallel resonance orientations. The critical angle and angular dependence of the position of the surface mode and the uniform mode were determined. The Surface Inhomogeneity (SI) model was applied with symmetrical boundary conditions. The surface anisotropy energy term was assumed as a superposition of the uniaxial anisotropy term and a biaxial anisotropy term. The origin of the latter term is not known yet. We also performed the resonance experiment for different temperatures ranging from 180 to 300 K. From the experiment, the uniaxial surface anisotropy constant K~l and the biaxial surface anisotropy constant K' 2 were found as functions of the temperature; the uniaxial anisotropy energy against temperature changes the sign for y = 0.02 from easy axis to easy plane while the biaxial surface anisotropy does not change its character.

Magnetocaloric effect of thin Dy films

Solid state communications, 2006

We report a theoretical study of the magnetocaloric effect (MCE) of Dy thin films, and show that the confinement of spins in the direction perpendicular to the surfaces leads to a considerable enhancement of the MCE. The adiabatic temperature change, T , for external field strength change, H , of the order of a few kOe, is much larger than what is found in bulk Dy, reaching T H = 6 K/T for ultra-thin films.

Uniaxial magnetic anisotropy for thin Co films on glass studied by magnetooptic Kerr effect

Journal of Applied Physics, 2011

Thin Co films of different thickness deposited on glass are investigated by magnetooptic Kerr effect to study the uniaxial magnetic anisotropy of these films. The direction of the uniaxial magnetic anisotropy is determined from the azimuthal dependence of the magnetic remanence and differs with increasing thickness of the Co film investigated by x-ray reflectivity. Our experiments reveal that preparation conditions like temperature, deposition rate, or obliqueness of deposition cannot be the reason for this rotation effect of the uniaxial magnetic anisotropy. Also, strain in the substrate and possible textures in the film structure can be excluded as the origin of the magnetic behavior as studied by grazing incidence wide angle x-ray scattering. Thus, probably only the substrate shape in connection with the amorphous or polycrystalline film structure can explain the rotation of the uniaxial magnetic anisotropy. V

Magnetic properties of Fe/Y multilayer thin films

Journal of Magnetism and Magnetic Materials, 1991

The results of saturation magnetization, magnetostriction constant and magneto-optical hysteresis loops in Fe/Y modulated thin films prepared by evaporation are reported. All the measurements have been performed at room temperature. It is demonstrated that the transformation of the Fe layers from amorphous structure to a bcc crystal has a strong influence on the magnetic properties of multilayers, In particular, magnetostriction constants are very sensitive to any structural transformation. Magnetic measurements suggest an additional collinear magnetic structure of Fe layers and absence of any observable interdiffusion between the layers.

Magnetic Structure, Anisotropy and Magneto-Optic Properties of Amorphous Rare-Earth Multilayers

Journal of the Magnetics Society of Japan, 1991

In this paper we discuss the atomic and magnetic structure of rare earth-transition metal compositionally modulated films with characteristic bilayer thicknesses in the nanometer range. A theoretical model based on singleion anisotropy and anisotropic pair correlations has been developed to understand the occurrence of perpendicular magnetic anisotropy for thin individual layers. Systematics of the magneto-optic properties of this class of materials are discussed, along with recent results on magnetization reversal mechanisms as studied by time decay of the Kerr effect.