First-Principles Study of Ti-Doping Effects on Hard Magnetic Properties of RFe11Ti Magnets.

Due to the rare earth supply shortage, ThMn₁₂-type RFe₁₂-based (R is the rare earth element) magnets with lean rare earth content are gaining more concern. Most ThMn₁₂-type RFe₁₂ structures are thermodynamically metastable and require doping of the stabilizing element Ti. However, the Ti-doping effects on the hard magnetic properties of RFe₁₁Ti have not been thoroughly investigated. Herein, based on density functional theory calculations, we report the Ti-doping effects on the phase stability, intrinsic hard magnetic properties and electronic structures of RFe₁₁Ti (R = La, Ce, Pr, Nd, Sm, Y, Zr). Our results indicate that Ti-doping not only increases their phase stability, but also enhances the magnetic hardness of ground-state RFe₁₂ phases. Particularly, it leads to the transition of CeFe₁₁Ti and PrFe₁₁Ti from easy-plane to easy-axis anisotropy. Charge density distributions demonstrate that Ti-doping breaks the original symmetry of the R-site crystal field, which alters the magnetic anisotropy of RFe₁₁Ti. Projected densities of states reveal that the addition of Ti results in the shift of occupied and unoccupied f-electron energy levels of rare earth elements, affecting their magnetic exchange. This study provides an insight into regulating the hard magnetic properties of RFe₁₂-based magnets by Ti-doping. [ABSTRACT FROM AUTHOR]