Генерация неравновесных зародышей намагниченности в быстро нарастающем магнитном поле в синтетических ферримагнетиках Pt/Co/Ir/Co/Pt

In a Pt/Co/Ir/Co/Pt synthetic ferrimagnet with perpendicular magnetic anisotropy, stochastically occurring peak of magnetic moment was detected in the rapidly increasing magnetic field of 16 kOe / s sweep rate at T = 300 K. The peak arises at the coinciding switching fields between three equilibrium magnetization states. The reason of the peak is nucleation of the nonequilibrium magnetic domains in the vicinity of structural defects of the Co film, where diminished activation energy of magnetic nucleation takes place.

Magnetoelasticity of gels

Magnetoelastic gel is an active material that is used widely these days. The behavior of these multifunctional gels is derived from a polymer matrix and magnetoresponsive inclusions. The polymer matrix provides structural integrity as well as load bearing capacity to the magnetoelastic gel. The magnetic behavior of the magnetoelastic gel is attributed to a large number of nano-to-micron-sized magnetic particles disbursed in the polymer matrix. The magnetoelastic gel is said to be diluted if the interparticle interactions are negligible/small or concentrated if there are strong interparticle interactions. We consider strong interparticle interactions in the magnetoelastic gel. When the magnetic field is applied to the magnetoelastic gel, the disbursed magnetic particles tend to translate and rotate to a new deformed configuration. Due to these translations and rotations of the many magnetoelastic particles, the polymer matrix around each particle deforms. These micro-deformations then coalesce and lead to the overall macroscopic deformation of the magnetoelastic gel. Both magnetization and mechanical strain characterize the magnetoelastic behavior of the magnetoelastic gel. In this article, an energy minimization approach is followed to find the equilibrium magnetization and strain. We formulate the total energy of the magnetoelastic gel on multiple-length scales and minimize it to obtain these equilibrium magnetization and mechanical strain. We also investigate the effect of particle size and polarization under the framework of energy minimization.

INVESTIGATION OF ANGULAR AND TEMPERATURE DEPENDENCE OF SPIN-WAVE RESONANCE SPECTRA IN MULTILAYER MAGNETIC FILMS

In this letter we study the dependences of the resonance field Hn and the linewidth 2ΔHn of the spin-wave resonance (SWR) modes in two-layer ferrite-garnet films with dissipative and mixed spinpinning mechanisms. It is established that for films with a dissipative mechanism of spin pinning, the increase in the linewidth at ΘH = 35° is associated with the maximum misorientation between the external magnetic field and the direction of the equilibrium magnetization of the sample. For films with a mixed spin-pinning mechanism, an increase in the linewidth 2ΔHn with increasing angle ΘH is associated with an increase in the depth of penetration of the spin wave into the pinning layer for such films. On the temperature dependence of the linewidth 2ΔHn for samples with a mixed fixation mechanism at a perpendicular orientation, an increase in the width of the absorption peak lines is observed. And with an increase in the peak number, the maximum of the linewidth shifts to the low-temperature region. With parallel orientation, the linewidth 2ΔHn in a wide temperature range from 20°C to 200°C remains practically unchanged.