The electronic and magnetic properties of cobalt-based layered oxypnictides, LaCoOX (X = P, As), are investigated. LaCoOP and LaCoOAs show metallic type conduction, and the Fermi edge is observed by hard x-ray photoelectron spectroscopy. Ferromagnetic transitions occur at 43 K for LaCoOP and 66 K for LaCoOAs. Above the transition temperatures, temperature dependence of the magnetic susceptibility follows the Curie-Weiss law. X-ray magnetic circular dichroism (XMCD) is observed at the Co L2,3-edge, but not at the other edges. The calculated electronic structure shows a spin polarized ground state. These results indicate that LaCoOX are itinerant ferromagnets and suggest that their magnetic properties are governed by spin fluctuation.
@article{arxiv.0806.0123,
title = {Itinerant Ferromagnetism in layered crystals LaCoOX (X = P, As)},
author = {Hiroshi Yanagi and Ryuto Kawamura and Toshio Kamiya and Yoichi Kamihara and Masahiro Hirano and Tetsuya Nakamura and Hitoshi Osawa and Hideo Hosono},
journal= {arXiv preprint arXiv:0806.0123},
year = {2008}
}
Comments
16 pages, 9 figures, Physical Review B, in press. Received 17 February 2008. Accepted 29 May 2008