Inverted Surface Hysteresis Loops in Heterogeneous (Nanocrystalline/Amorphous) Fe81Nb7B12 Alloys.

Inverted hysteresis loops were observed for the first time in the near-surface layers of heterogeneous (nanocrystalline/amorphous) Fe₈₁Nb₇B₁₂ alloys. In particular, a negative residual magnetization is retained when a positive magnetic field applied in the sample plane is decreased to zero. The inverted hysteresis is qualitatively explained within the framework of a two-phase model, according to which the heterogeneous alloys contain two dissimilar phases exhibiting uniaxial magnetic anisotropy and featuring antiferromagnetic exchange interaction. © 2004 MAIK “Nauka / Interperiodica”. [ABSTRACT FROM AUTHOR]