Growth and Characterization of Ce- Substituted Nd2Fe14B Single Crystals

TL;DR

This study explores the growth, structure, and magnetic properties of Ce-substituted Nd2Fe14B single crystals, demonstrating that Ce substitution slightly reduces magnetic performance but maintains potential for high-performance permanent magnets.

Contribution

It provides new insights into Ce substitution effects on Nd2Fe14B, including growth methods, structural analysis, and magnetic property evaluation, highlighting its viability for applications.

Findings

Ce can substitute Nd in Nd2Fe14B up to x=0.38 with minimal structural disruption.

Magnetic properties decrease with Ce substitution but remain suitable for applications.

Ce-substituted Nd2Fe14B retains high magnetic performance with reduced Nd content.

Abstract

Single crystals of (Nd1-xCex)2Fe14B are grown out of Fe-(Nd,Ce) flux. Chemical and structural analysis of the crystals indicates that (Nd1-xCex)2Fe14B forms a solid solution until at least x = 0.38 with a Vegard-like variation of the lattice constants with x. Refinements of single crystal neutron diffraction data indicate that Ce has a slight site preference (7:3) for the 4g rare earth site over the 4f site. Magnetization measurements show that for x = 0.38 the saturation magnetization at 400 K, a temperature important to applications, falls from 29.8 for the parent Nd2Fe14B to 27.6 (mu)B/f.u., the anisotropy field decreases from 5.5 T to 4.7 T, and the Curie temperature decreases from 586 to 543 K. First principles calculations carried out within density functional theory are used to explain the decrease in magnetic properties due to Ce substitution. Though the presence of the lower-cost and more abundant Ce slightly affects these important magnetic characteristics, this decrease is not large enough to affect a multitude of applications. Ce-substituted Nd2Fe14B is therefore a potential high-performance permanent magnet material with substantially reduced Nd content.