Absorption résonnante ferromagnétique pour les couches minces électrolytiques de Ni-Fe-Mo avec anisotropie biaxiale

Abstract

Magnetic absorption resonance is studied in electrodeposited thin films of permalloy (80% Ni) and permalloy with Mo (5% Mo) having biaxial anisotropy achieved by ferromagnetic coupling. The film thickness was 5300 Å. The anisotropy field has values which decrease from 9.6 to 9 Oe for films without Mo and from 5.8 to 3.1 Oe for films with 5% Mo when the working frequency increases from 3 to 9 MHz. The angle between the axes is 20° in both cases. The effective damping parameter corresponding to the precession of the magnetic moment around an equilibrium direction of the constant field perpendicular to the anisotropy axis, decreases with the increase of r.f. field from 3 to 9 MHz as follows: from 0.35 to 0.10 for the films without Mo and from 0.65 to 0.32 for the films with Mo, the angle between the axes being of 20° in both cases. For the precession of the magnetic moment around a direction perpendicular to the second axis, the effective damping parameter decreases from 0.27 to 0.10 for films without Mo and from 0.66 to 0.28 for films with Mo for the same angles between axes and over the above frequency range.