Half-Metallic Ferromagnetism and Large Negative Magnetoresistance in the New Lacunar Spinel GaTi3VS8

• Published in: Journal of the American Chemical Society Vol. 132; no. 16; pp. 5704 - 5710
• Main Authors: Dorolti, Eugen, Cario, Laurent, Corraze, Benoît, Janod, Etienne, Vaju, Cristian, Koo, Hyun-Joo, Kan, Erjun, Whangbo, Myung-Hwan
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 28.04.2010
• Subjects: Condensed Matter; Materials Science; Physics
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/ja908128b

The lacunar spinel compounds GaTi4−x V x S8 (0 < x < 4), consisting of Ti4−x V x tetrahedral clusters, were prepared and their structures were determined by powder X-ray diffraction. The electronic structures of GaTi4−x V x S8 (x = 0, 1, 2, 3) were examined by density functional calculations, and the electrical resistivity and magnetic susceptibility of these compounds were measured. Our calculations predict that GaTi3VS8 is a ferromagnetic half-metal, and this prediction was confirmed by magnetotransport experiments performed on polycrystalline samples of GaTi3VS8. The latter reveal a large negative magnetoresistance (up to 22% at 2 K), which is consistent with the intergrain tunnelling magnetoresistance expected for powder samples of a ferromagnetic half-metal and indicates the presence of high spin polarization greater than 53% in GaTi3VS8.