Abstract:

Since the χ″ non-linearly changes following the magnetic field H in the ferromagnetic sample,  there is a low field (0～12 mT) non-resonance signal having a comparable strength with that of the ferromagnetic resonance signal. With the ESR spectrometer,  the change dχ″/dH]～H is measured，and then study dynamic magnetization of the alloy ribbon Fe₈₄Zr_3.5Nb_3.5B₈Cu₁. The sample of alloy ribbon is anisotropic,  the easy (magnetization) axis of the sample is in the lateral direction of the ribbons,  and the H is at this direction. It is found that dχ″/dH=0 in the regions of the reversible  (0～2.0 mT) and saturation magnetization (≥9.0 mT). When the domain wall motion is nonreversible, the χ″(H) is the largest value χ_max when the H is 4.2 mT. And χ″is relevant to H² during the domain rotation (Rayleigh region). It is found however in the experiment that the χ″(H) being in proportion to H² and Hⁿ(n≥3) are alternatively formed in  three sections. During this process,  the magnetic fields that the dχ″/dH is constants are 4.8～5.2 mT, 5.8～6.4 mT and 8.0～8.5 mT respectively. The macroscopic phenomenon,  that dχ″/dH equals non-zero constant or not alternatively is a microscopic demonstration that domain wall motion and domain rotation.

Key words: ESR, Low field non-resonance signal, magnetic process, domain wall motion, domain rotation, microwave property