Effect of annealing in an external magnetic field on the magnetic texture of Mo-containing nanocrystalline alloys

Abstract

The magnetic texture of (Fe1−x Cox)76Mo8Cu1B15 (x = 0, 0.5) nanocrystalline alloys is studied for different amounts of nanocrystalline grains. The originally amorphous alloys were annealed in external longitudinal and transverse magnetic fields of 0.025 T and 0.8T, respectively. Mossbauer measurements were carried out at room and liquid nitrogen temperatures in order to gain information on the hyperfine interactions and the orientation of the magnetization. The obtained results are compared with those received from zero-field annealed samples. Magneto-optical Kerr effect (MOKE) was applied for the investigation of possible changes at the surface of the x = 0 ribbon as a function of annealing temperature and applied magnetic field. A combination of uniaxial anisotropy, which originates from the shape anisotropy, and four-fold anisotropy, which is a contribution from crystallites of nanometre size embedded in the residual amorphous matrix, is unveiled.