DOMAIN-WALL PINNING AND HYSTERESIS LOSSES IN AMORPHOUS CONBZR FILMS

In a series of CoNbZr amorphous films prepared by R.F. sputtering, with thickness t ranging from 86 to 480 nm, we show that the domain wall (DW) motion is the dominant magnetization mechanism in the irreversible processes when the magnetic field is applied along the in-plane easy axis. A simple model, assuming a DW pinning at the film surfaces, explains the existence of a critical unpinning field (as well as hysteresis losses) inversely proportional to the film thickness. Frequency effects on loop parameters are reported up to 100 kHz.