Multi-jump magnetic switching in ion-beam sputtered amorphous Co_(20)Fe_(60)B_(20) thin films

摘要

Unconventional multi-jump magnetization reversal and significant in-plane uniaxial magnetic anisotropy (UMA) in the ion-beam sputtered amorphous Co_(20)Fe_(60)B_(20)(5-75 nm) thin films grown on Si/amorphous SiO_2 are reported. While such multi-jump behavior is observed in CoFeB(10nm) film when the magnetic field is applied at 10°-20° away from the easy-axis, the same is observed in CoFeB(12.5nm) film when the magnetic field is 45°-55° away from easy-axis. Unlike the previous reports of multi-jump switching in epitaxial films, their observance in the present case of amorphous CoFeB is remarkable. This multi-jump switching is found to disappear when the films are crystallized by annealing at 420 ℃. The deposition geometry and the energy of the sputtered species appear to intrinsically induce a kind of bond orientation anisotropy in the films, which leads to the UMA in the as-grown amorphous CoFeB films. Exploitation of such multi-jump switching in amorphous CoFeB thin films could be of technological significance because of their applications in spintronic devices.