Temperature dependence of the FMR absorption lines in viscoelastic magnetic materials

Thermal Effects on the Ferromagnetic Resonance in Polymer Composites with Magnetic Nanoparticles Fillers

“…The larger temperature is the larger the rotational oscillations are. Besides the spring force the anisotropy axis experiences the magnetic torque which is represented by two opposite point forces (Dudek et al, 2010) applied to the anisotropy axis with the strength…”

“…This special property of viscous magnetic materials has been studied experimentally for maghemite nanoparticles embedded in a multiblock poly(ether-ester) copolymer nonmagnetic matrix Guskos et al (2006;. The experiments were performed in a wide range of temperatures, 3.5-288 K. In addition to the experimental results were also carried out theoretical studies Dudek et al (2010). Several examples of spectral lines discussed in Dudek et al (2010) are presented in Fig.…”

“…The experiments were performed in a wide range of temperatures, 3.5-288 K. In addition to the experimental results were also carried out theoretical studies Dudek et al (2010). Several examples of spectral lines discussed in Dudek et al (2010) are presented in Fig. 6 for concetration of 0.1% of γ-Fe 2 O 3 nanoparticles dispersed in the polymer matrix.…”

“…As a particular example, we consider the FMR experiment with the γ-Fe 2 O 3 (maghemite) ferrimagnetic nanoparticles embedded in a multiblock poly(ether-ester) copolymer nonmagnetic matrix which has been studied both experimentally (Guskos et al, 2006; and theoretically (Dudek et al, 2010). However, the obtained results are general and applicable to other nanoparticles and other viscous materials.…”

“…In the latter case stochastic equations were used both for the magnetic nanoparticles magnetization and the rotational oscillations of the magnetic nanoparticles as a whole. The influence of the magnetic anisotropy orientation and temperature on the FMR spectra of magnetic agglomerates in polymer matrix was discussed in (Dudek et al, 2010). The most important property of the FMR spectrum depending on temperature will be discussed in the sections below.…”