Exchange interactions, spin waves, and Curie temperature in zincblende half-metallic sp-electron ferromagnets: the case of CaZ (Z = N, P, As, Sb)

• Published in: Journal of physics. Condensed matter Vol. 23; no. 29; pp. 296001 - 6
• Main Authors: Laref, A, Şaşioglu, E, Galanakis, I
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 27.07.2011; Institute of Physics
• Subjects: Condensed matter; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Constants; Curie temperature; Exact sciences and technology; Exchange; Ferromagnetism; Magnetic properties and materials; Magnetically ordered materials: other intrinsic properties; Mathematical analysis; Physics; Spin waves; Zincblende; II-V semiconductors; Dispersion (wave); Spin waves; Curie point; Blende structure; Calcium compounds; Random phase approximation; Electronic density of states; Stoner model; Density functional method; Semimetals; Magnons; Exchange interactions
• ISSN: 0953-8984; 1361-648X
• DOI: 10.1088/0953-8984/23/29/296001

Using first-principle calculations in conjunction with the frozen-magnon technique we have calculated the exchange interactions and spin-wave dispersions in the series of the zincblende half-metallic II-V (CaZ, Z = N, P, As, Sb) ferromagnets. The calculated exchange constants are used to estimate the Curie temperature within the random phase approximation. The large Stoner gap in these alloys gives rise to well-defined undamped spin waves throughout the Brillouin zone. Moreover we show that the spin-wave stiffness constants for the considered systems are among the largest available for local moment ferromagnets. The predicted Curie temperature of half-metallic CaN is noticeably higher than the room temperature with respect to the other compounds, and thus we propose CaN as a promising candidate for future applications in spintronic devices.