Structural and magnetic properties of PrFe12-xVx and their nitrides

Citation
W. Mao et al., Structural and magnetic properties of PrFe12-xVx and their nitrides, ACT MATER, 49(4), 2001, pp. 721-728
Citations number
36
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science","Material Science & Engineering
Journal title
ACTA MATERIALIA
ISSN journal
1359-6454 → ACNP
Volume
49
Issue
4
Year of publication
2001
Pages
721 - 728
Database
ISI
SICI code
1359-6454(20010223)49:4<721:SAMPOP>2.0.ZU;2-0
Abstract
The structural and magnetic properties of novel permanent magnet materials, PrFe12-xVxNy (x = 1.25 similar to2.0; y approximate to1.6), have been stud ied systematically. It is shown that the nitrides crystallize in the same T hMn12-type structure as the parent alloys, with the unit cell volume expans ion upon nitrogenation. Neutron diffraction performed on PrFe10.5V1.5N0.4 a t room temperature reveals that the vanadium atoms occupy the Si sites, whi le the nitrogen atoms occupy the 2b sites and the iron atoms occupy the 8j, 8f and the rest 8i sites in the ThMn12-type structure. Typical interstitia l modification effects are observed in PrFe12-xVxN1.6. The Curie temperatur e is raised to as high as 800 K and the saturation magnetization is increas ed to 1.54 T at room temperature. Mossbauer spectra studies also show that the hyperfine field and isomer shift are strongly enhanced upon nitrogenati on. Nitrogenation changes the easy magnetization direction from the ab-plan e to the c-axis with an anisotropy field up to 10.5 MA/m (132 kOe). Crystal field coefficients For Pr3+ in PrFe12-xVx and PrFe12-xVxN are calculated t o explain this change in magnetocrystalline anisotropy behaviors. As a prel iminary attempt, the magnetically hard powders based on Pr(Fe,V)(12)N-1.6 a re obtained with a maximum energy product of 135 kJ/m(3) (16.9 MGOe) and a remanence of 1.18 T at room temperature. (C) 2001 Acta Materialia Inc. Publ ished by Elsevier Science Ltd. All rights reserved.