Electronic structures and Curie temperatures of iron-based rare-earth permanent-magnet compounds

Authors

J.P. Woods , University of Nebraska - Lincoln
B.M. Patterson, University of Nebraska - Lincoln
A.S. Fernando, University of Nebraska - Lincoln
Sitaram Jaswal, University of NebraskaFollow
D. Welipitiya, University of Nebraska - Lincoln
David J. Sellmyer, University of Nebraska-LincolnFollow

Document Type

Article

Date of this Version

January 1995

Comments

Published by American Physical Society. Phys. Rev. B 51, 1064 (1995). http://prb.aps.org. Copyright © 1995 American Physical Society. Permission to use.

Abstract

The modification of the electronic structures of Sm₂Fe_17-xAl_xN_y, NdFe₁₁TiN_y, and YFe_12-xMo_x upon alloying and nitriding are examined with self-consistent spin-polarized calculations and soft-x-ray photoemission measurements between 18 and 135 eV. The changes in the Curie temperature T_c with substitutional modifications and nitrogen addition are modeled with self-consistent spin-polarized electronic structure calculations and the spin-fluctuation theory of Mohn and Wohlfarth which relates the electronic structure to T_c. The calculations show that the spin-summed density of states at the Fermi energy is related to T_c. The photoemission spectra are dominated by the Fe 3d electrons within 3 eV of the Fermi energy in agreement with calculations. Changes in the density of states at the Fermi energy for interstitial and and substitutional modification compare well with calculations. Using photoemission results with experimental magnetic moments for the substitutional modification of the compound Sm₂Fe_17-xAl_x, the spin-fluctuation theory predicts a change in T_c in agreement with the measured change in T_c. Spin-resolved photoemission spectra for c-axis oriented Sm₂Fe₁₇N_2.6 with magnetization perpendicular to the surface are presented and compared to theoretical calculations.