Magnetization reversal processes of nanostructured PrFeB alloys

Abstract

The paper considers the high-coercivity state of the melt-spun PrFeB alloys with different phase composition: the main Pr2Fe14B phase grains separated by the paramagnetic layers, single-phase state (Pr2Fe14B grains only), and combination of Pr2Fe14B and α-Fe phase grains. The phase composition and microstructure of the alloys, as well as their magnetic properties in the temperature range of 2–300 K are given. To establish the prevailing mechanism of the high-coercivity state, magnetometric techniques were used, including the study of the reversible magnetic susceptibility, and simulations by the finite difference method. The simulations of the magnetization reversal of these alloys demonstrate the complexity of this processes, which go beyond simple nucleation or pinning, and cannot be described in the framework of the Kneller-Hawig model. Models of magnetization reversal of the alloys under study are proposed. The presence and composition of the intergranular layer has a significant effect on the mechanism of the high-coercivity state.