Asymmetric magnetization reversal processes in amorphous composites (Fe40Co40B20)x(AL2O3)100-x

Abstract

The amorphous composite films (Co40Fe40B20)x(Al2O3)100-x with different content of the metal (Co40Fe40B20)x “(CoFeB)x” and the dielectric (Al2O3)100-x components were obtained in the original ion-beam deposition unit. Sputtering of a composite target from an amorphous Co40Fe40B20 alloy plate with dielectric Al2O3 inserts was carried out in the argon atmosphere at an operating pressure of ∼5.10–4 Torr on glass-ceramic Sitall substrates. The presence of two regions in the IR spectra of composites with different values of х confirms the existence of the metal and dielectric components during the ion-plasma deposition of composites on a sitall substrate as a result of self-arrangement. The magnetic hysteresis was measured at room temperature for (CoFeB)x(Al2O3)100-x thin film samples for x = 1, 75 and from 9 to 69 with the step x = 10 at different angles (φ) when magnetic field applied out of a plane (φ = 90°) and in-plane (φ = 0°) of the films. The obtained results show that at low alloy (CoFeB)x contents the film composites with nominal x = 1, 9, and 19 behave as paramagnetic from the first glance. With an increase of the alloy (CoFeB)x content to nominal x = 29–75 amorphous composites films seems as superparamagnetic and ferromagnetic materials that are characterized as reversal magnetization with no coercivity and remanence. The existence of a magnetic vortex in the samples with x = 59–75 opens different remarkable applications like data storage.