Large anisotropic magnetoresistance of ruthenium-based Heusler alloys

• Published in: Journal of applied physics 2009-04, Vol.105 (7), p.07E513-07E513-3
• Main Authors: Mizusaki, S., Ohnishi, T., Douzono, A., Nagata, Y., Ozawa, T. C., Samata, H., Noro, Y.
• Format: Article
• Language: English
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.3080561

Anomalous magnetic behavior was found in the polycrystalline Heusler alloy system Ru 2 Mn 1 − x Fe x Ge . Samples of x = 0 and 1.0 show no magnetoresistance (MR); however, the anisotropic MR effect is observed for x = 0.5 (MR ratios of −4% and + 2 % are observed under parallel and perpendicular configurations of applied field and applied current, respectively). Moreover, magnetic measurement revealed that the sample of x = 0 is antiferromagnetic, whereas the samples of x = 0.5 and 1.0 are ferromagnetic with Curie temperatures of 270 and 490 K, respectively. The saturation magnetization and coercivity at 5 K are 3.1 μ B / f .u . and negligibly small for x = 1.0 and 1.8 μ B / f .u . and 0.1 T for x = 0.5 , respectively. The MR effect is explained by a model in which antiferromagnetic and ferromagnetic domains coexist.