Effects of Crystal Anisotropy, Grain and Domain Sizes on Coercovity Mechanism of the Nd-Fe-B Sintered Magnets

Abstract

The Dy free and Dy substituted (0 100) Nd Fe B sintered magnets based on the NEOMAX 50 type magnet were prepared, and the magnetic properties such as the saturation magnetizations, the coercivities and the magnetic anisotropy constants (K 1 , K 2 ) were determined by the obtained data using an high field magnetometer. The domain structures, especially domain widths were measured using MOKE and SEM, and the sizes of magnetic interacted regions were calculated based on the resulted values. The coercivity of the magnets is subjected to, first: the magnetic anisotropy field, second: crystal grain sizes, third: size of group of crystal grains behaving as a cooperated region that reflects the magnetic interaction through the grain boundary (GB).

Electronic structure of the (Nd1−xDyx)2Fe14B (0 ≤ x ≤ 1) system studied by X-ray photoelectron spectroscopy

“…Moreover, the substitution of Dy for Nd in Nd 2 Fe 14 B results in a linear increase in H A and a corresponding linear decrease in M s . [7][8][9][10] Since the magnetic property is sensitive to the electronic structure, a preliminary speculation is proposed that the electronic structure in the (Nd 1−x Dy x ) 2 Fe 14 B system would be in a linear variation. The purpose of our work is to confirm this speculation.…”