Microstructure, domain walls, and magnetization reversal in hot-pressed Nd-Fe-B magnets

Abstract

Transmission electron microscopy study of hot-pressed and hot-deformed Nd0.14(Fe0.94B0.06)0.86 magnets shows that the magnetic alignment is achieved by the formation of a microstructure consisting of platelets of Nd2Fe14B grains with the c axis normal to the platelet surface and parallel to the press direction. Magnetic domain walls, lying parallel to the c axis, run through many grains and are pinned at the intergranular phases that are produced during processing. Magnetization reversal occurs by domain wall motion.

The history of permanent-magnet materials

“…In China, they were known as "loving stones" because their attraction for pieces of iron was symbolic of the love parents had for their children. s Building on the word "lode" (Middle English for" course"), they later became known as "lodestones" because of their 30 use, and the use of iron needles magnetized by them, as compasses for navigation.…”

Relationship between microstructure and magnetic domain structure of Nd-Fe-B melt-spun ribbon magnets

“…It is important for the problem to establish the coercivity mechanism of Nd-Fe-B magnet through microstructure observation. There are many reports about the relation between the coercivity and microstructure of Nd-Fe-B magnets [3][4][5][6][7]. In addition, it is important to clarify the relation between the microstructure and the domain structure of the magnet.…”

Coercivity and exchange coupling in PrCo:Co nanocomposite films

“…For sample a with multilayer structure (PrCo30 nm/Co11 nm) ϫ10, the initial curve is similar to that expected in a nucleation-type mechanism of coercivity; whereas for sample d with multilayer structure (PrCo30 nm/Co5 nm) ϫ10, the initial curve is typical for wall-pinning controlled reversal. However, in case of nanoscale morphology, one may have to consider interaction domains, 7,8 because simple nucleation and pinning models might not adequate for describing the coercivity mechanism. A study of the details of coercivity mechanism is underway and will be reported later.…”