Effects of spacer layers on magnetic properties and exchange couplings of Nd–Fe–B/Nd–Ce–Fe–B multilayer films

Abstract

The influences of the spacer-layer Ta on the structures and magnetic properties of NdFeB/NdCeFeB multilayer films are investigated via DC sputtering under an Ar pressure of 1.2 Pa. An obvious (00l) texture of the hard phase is observed in each of the films, which indicates that the main phase of the film does not significantly change with Ta spacer-layer thickness. As a result, both the remanence and the saturation magnetization of the magnet first increase and then decrease, and the maximum values of 4πM r and H cj are 10.4 kGs (1 Gs = 10 −4 T) and 15.0 kOe (1 Oe = 79.5775 A•m −1 ) for the film with a 2-nm-thick Ta spacer-layer, respectively, where the crystalline structures are columnar shape particles. The measured relationship between irreversible portion D(H) = −∆M irr /2M r and H indicates that the nucleation field of the film decreases with spacer layer thickness increasing, owing to slightly disordered grains near the interface between different magnetic layers.

Coercivity enhancement of sputtered (La,Nd,Dy)-Fe–Co–B multilayers by inserting Ta space layers

“…Cui et al [25] reported that the coercivity of Ce-Fe-B film could be enhanced due to higher Nd composition in the GBs and grain surfaces region by diffusing Nd. Sun et al [26] studied the exchange coupling and influence of the thickness of Ta space layer on magnetic properties of Nd-Fe-B/Nd-Ce-Fe-B multilayer.…”