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The transverse magnetization and longitudinal magnetization hysteresis loops of sputtered thin films of Fe/Ge and Fe/Si multilayers on GaAs(001) substrates have been studied. The dependence of the film magnetic anisotropy on the bilayer period and semiconductor composition was investigated using a MOKE magnetometer. The hysteresis loops were measured as a function of the angle between the applied magnetic field and the hard–hard axis of the film. For the longitudinal magnetization, the Fe/Si film loops had lower remanent magnetization compared to the Fe/Ge film with the same spacer thickness. Thus the Fe/Si film had stronger exchange coupling across the spacer layer compared to the Fe/Ge film. For the thicker Ge spacer layer film, no exchange coupling was measured. For the transverse magnetization, the Fe/Ge multilayer films loops had only one Barkhausen jump. For the Fe/Si multilayer films loops, some contained one Barkhausen jump while others had two jumps, due to the cubic anisotropy contribution. These results are interpreted in terms of anisotropy and exchange energies.

Magnetization reversal of a Fe/Si/Fe trilayer having a ferromagnetic bilinear and biquadratic exchange is investigated at 10 and 300 K. The experiments were performed using the magneto-optical Kerr effect technique and a SQUID magnetometer. The type of stable magnetic configuration is determined for both temperatures of the study. The hysteresis loops contain jumps in magnetization, which could be associated with the overcoming of the energy barriers related to the uniaxial anisotropy hard axes in the two iron layers. The analysis of the experimental results was performed in the framework of a model in which the ferromagnetic bilinear and biquadratic exchange between two magnetic layers separated by a nonmagnetic spacer and the cubic and uniaxial anisotropy were taken into account. Good qualitative agreement is obtained between the experimental and calculated field dependences of the magnetization.

Magnetostriction measurements were performed at different temperatures for Fe81Si3.5B13.5C2 METGLAS® films using a strained substrate technique. The magnetostriction constant was deduced from magnetic properties measured using a vibrating sample magnetometer. The film strain was varied using a range of curved sample holders. From the change of magnetic anisotropy field as a function of controlled strain, the saturation magnetostriction constant can be determined with sufficient accuracy. The temperature dependence of magnetostriction of METGLAS® Fe81Si3.5B13.5C2 from 9 to 287 K is reported. It is suggested that a single-ion mechanism of magnetostriction is dominant in this amorphous alloy.

Magnetostrictive FeCo films (thickness 300 nm) have been produced by RF magnetron sputter deposition. The effects of the substrate, composition and thermal treatment on the structural and magnetic properties of the films have been determined. Structural analysis was performed using transmission electron microscopy and x-ray diffraction. The magnetic properties, including magnetostriction, were determined by the magneto-optical Kerr effect, magnetic force microscopy and strain-modulated ferromagnetic resonance. It is found that the magnetic softness of the films is critically dependent on the texture and strain state of the film. With suitable choices of substrate, composition and thermal treatment, these parameters can be controlled, producing magnetically soft films while maintaining a high magnetostriction. The differential response of the magnetic anisotropy to strain in these films is comparable to the best values achieved by more involved manufacturing processes, such as multilayering, showing excellent potential for their use in magnetic sensors and actuators.

EPR measurements have been performed in the temperature range 4.2-295 K on a polycrystalline sample of the linear chain system MnC2O4.2D2O. The temperature dependence of the width of the resonance line has been analysed in terms of the available theory for a one-dimensional antiferromagnet.

The EPR spectrum of Gd3+ ions diluted (0.5% and 0.1%) in powdered samples of the high-Tc(Tc-92 K) superconductor Y1Ba2Cu3Ox has been measured at X-band in the temperature range 4.2-300 K. It was shown that the EPR spectrum exhibits significant changes in g-shift, thermal broadening and intensity well below Tc. The results are analysed in terms of existing theoretical models.

The forced magnetostriction arising from the magnetic field dependence of the volume and linear magnetostriction of amorphous alloys is calculated within the random anisotropy model. It is shown that forced magnetostriction in amorphous materials is determined by several mechanisms with different origins.