The results of experimental investigation of free oscillations of magnetization in garnet-ferrite films with planar anisotropy are considered. It is shown that the damping decrement of free oscillations increases with effective anisotropy field H (Kp) .

Abstract Nonlinear oscillations of magnetization (with a fundamental harmonic frequency of ≈0.5 GHz) emerging during 90°-pulsed magnetization of garnet ferrite films with easy-plane anisotropy are studied. Analysis of longitudinal and transverse magnetization signals and of the magnetization vector hodograph plotted on their basis shows that the weak dependence of the oscillation intensity on duration t f of the magnetizing magnetic field pulse (upon its variation from 0.4 to 6–8 ns), which is typical of these films, can be explained by the presence of biaxial anisotropy in the plane of actual films.

The magnetization vector hodographs corresponding to the regime of 90° pulse magnetization of ferrite-garnet films with easy-plane anisotropy have been analyzed. It is found that when the magnetizing pulse amplitude H m exceeds some threshold value H * m (≈15 Oe), magnetization occurs through the mechanism of uniform magnetization vector rotation. The weak dependence of the intensity of nonlinear oscillations (accompanying the magnetization process) on the rise time of the magnetizing pulse, observed in the fields H m > H * m , is explained by the presence of biaxial anisotropy in the plane of real films.

The curves of pulsed magnetization reversal in iron garnet films with easy-plane anisotropy are studied. Magnetization reversal is initiated by a pulsed magnetic field aligned with the axis of biaxial anisotropy lying in the plane of the film. The curves exhibit kinks at fields close to the effective field of biaxial anisotropy. Magnetization reversal mechanisms in fields above and below the inflection point are discussed.

A method of studying biaxial anisotropy in ferrite-garnet films with in-plane magnetization is considered. To ensure the maximum reliability in a comparison between the pulse properties of a film and its anisotropy the latter is investigated by means of a pulse inductive apparatus. For the identification of the anisotropy axes the dependence of the shape of the 180°-pulse reversal signal on the direction of the switching field is analyzed. The value of the effective anisotropy field, was measured by the method of free magnetization oscillations.

The magnetizer is intended for studies of transient processes in magnetic samples shaped as plates or planar films. The main element of the magnetizer is a strip line consisting of thin wires connected in series with damping resistors. The use of resistors makes it possible to reduce the eddy current decay time (and, therefore, the magnetic field settling time) to ∼5–6 ns and, in turn, to extend the range of durations of the processes under study and increase the spatial homogeneity of the field. The magnetization of samples is measured using a removable longitudinal sence loop. The magnetizer can be used to study a wide variety of transient processes with a duration of ∼0.05–100 μs (in permalloy films, iron borate single crystals, garnet ferrite films with easy-plane anisotropy, etc.). The magnetizer can also be used to observe dynamic domains.

It is established that the magnitude of the discontinuity in the slope of a pulse-switching curve defined as the ratio between the switching coefficients Sw1 and Sw2 corresponding to the first and second parts of the switching curve, respectively, decreases with an increase in the thickness of a ferrous borate single crystal. This change is generally caused by a decrease in the coefficient Sw1, whose magnitude is inversely proportional to the sample’s thickness. In order to analyze the results obtained, we used the early proposed expression τ−1=aH s −,bA2, connecting the switching rate τ−1 with the amplitude of the magnetic field Hs and the intensity A of the magnetoelastic vibrations accompanying the pulse switching. It is found that the coefficient a depends only slightly on the sample’s thickness, while the coefficient b is inversely proportional to the thickness squared. Thus, the main part of the energy losses due to magnetoelastic vibrations is associated with elastic lattice vibrations.

A generalized expression is suggested for the description of the influence of the characteristics of dynamic domains and the effective anisotropy field on the threshold field H 0 for the mechanism of bisensical incoherent rotation of magnetization and fields H 4 and H 5 that correspond to the fourth and fifth inflection points in the pulse switching curve reflecting sharp quantitative and qualitative changes in this mechanism. Expressions are derived for the switching time in the fields H 4 and H 5 . The results of calculations are confirmed by experimental data.

This paper describes the first investigations of the process of pulsed 180° magnetization reversal in iron borate in the presence of a transverse magnetic field. How the intensity of magnetoelastic oscillations depends on the amplitude of the magnetization reversal field and the duration of the primary period of the transient process is studied, and also the analysis of hodographs of the magnetization vector, which show that the primary reason why the pulsed magnetization reversal curve exhibits a kink is a decrease in the energy lost to excitation of magnetoelastic oscillations, caused by lagging of the elastic subsystem of the crystal behind the magnetic subsystem for magnetization reversal times less than 13–16 ns.

Experimentally found threshold fields for nucleation, H n , and for the irreversible rotation of magnetization, H Or , were compared for the first time. The irreversible rotation was measured by a technique proposed earlier by Crowter to determine the magnitude dispersion of the anisotropy. In most Permalloy films, H n was found to be close to H Or in magnitude.

For the first time, photographs of dynamic domains produced in the course of magnetization reversal in amorphous Fe 5 Co 70 Si 15 B 10 films within the bounds of the third section of the pulse magnetization reversal curve were obtained. It was established that the magnetization reversal takes place by means of monotonic rotation of magnetization inside stripe domains oriented at right angles to the easy axis.

For the first time, photographs of dynamic domains produced in the course of magnetization reversal in amorphous Fe 5 Co 70 Si 15 B 10 films within the bounds of the third section of the pulse magnetization reversal curve were obtained. It was established that the magnetization reversal takes place by means of monotonic rotation of magnetization inside stripe domains oriented at right angles to the easy axis.

The prupose of this paper was to draw attention to the influence of one factor associated with the layer nature of real films. The clearest manifestation of the layer nature was this: the presence of several layers with different values of the magnetization, effective anisotropy field

The prupose of this paper was to draw attention to the influence of one factor associated with the layer nature of real films. The clearest manifestation of the layer nature was this: the presence of several layers with different values of the magnetization, effective anisotropy field