2008/06/01 by Hiroshi Yanagi, Ryuto Kawamura, Toshio Kamiya +5 · 1 citation
Business, Management and Accounting · Materials Science · Physics and Astronomy · #Corporate Taxation and Avoidance #Iron-based superconductors research #Rare-earth and actinide compounds #cond-mat.str-el #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.77.224431
published as Phys. Rev. B 77, 224431 (2008) · 16 pages, 9 figures, Physical Review B, in press. Received 17 February 2008. Accepted 29 May 2008
arxiv created 2008/06/01 · openalex publication_date 2008/06/20 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
The electronic and magnetic properties of cobalt-based layered oxypnictides, LaCoOX(X=P,As), are investigated. LaCoOP and LaCoOAs show metallic type conduction with room-temperature resistivities of \ensuremath∼2\ifmmode×\else\texttimes\fi10^\ensuremath-4 \ensuremathΩ cm, 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 with spontaneous magnetic moments of 0.33\ensuremathμB and 0.39\ensuremathμB extrapolated to 0 K, respectively. Above the transition temperatures, the magnetic susceptibility exhibits a large temperature dependence. Provided that this temperature dependence follows the Curie-Weiss law, enhanced magnetic-moment values of \ensuremath∼2.9\ensuremathμB for LaCoOP and \ensuremath∼1.3\ensuremathμB for LaCoOAs are obtained. 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 with a magnetic moment of 0.52\ensuremathμB, \ensuremath∼95% of which is localized on the Co ions. These results indicate that LaCoOX are itinerant ferromagnets and suggest that their magnetic properties are governed by spin fluctuation.