Transport Spin Polarization of High-Curie Temperature MnBi Films

Authors

Parashu Kharel, University of Nebraska-LincolnFollow
P. Thapa, Wayne State UniversityFollow
Pavel V. Lukashev, University of Nebraska-LincolnFollow
Renat F. Sabirianov, University of Nebraska at OmahaFollow
Evgeny Y. Tsymbal, University of Nebraska-LincolnFollow
D. J. Sellmyer, University of Nebraska-LincolnFollow
Boris Nadgorny, Wayne State UniversityFollow

Date of this Version

2011

Citation

PHYSICAL REVIEW B 83, 024415 (2011). DOI: 10.1103/PhysRevB.83.024415

Comments

Copyright © 2011 American Physical Society. Used by Permission

Abstract

We report on the study of the structural, magnetic, and transport properties of highly textured MnBi films with the Curie temperature of 628 K. In addition to detailed measurements of resistivity and magnetization, we measure transport spin polarization of MnBi by Andreev reflection spectroscopy and perform fully relativistic band-structure calculations of MnBi. A spin polarization from 51% ± 1% to 63% ± 1% is observed, consistent with the calculations and with an observation of a large magnetoresistance in MnBi contacts. The band-structure calculations indicate that in spite of almost identical densities of states at the Fermi energy, the large disparity in the Fermi velocities leads to high transport spin polarization of MnBi. The correlation between the values of magnetization and spin polarization is discussed.