Ferromagnetism at the surface of a LaCoO3 single crystal observed using scanning SQUID microscopy

被引：36

作者：

Harada, A.

Taniyama, T.

Takeuchi, Y.

Sato, T.

Kyomen, T.

Itoh, M.

机构：

[1] Tokyo Inst Technol, Mat & Struct Lab, Midori Ku, Yokohama, Kanagawa 2268503, Japan

[2] Keio Univ, Dept Appl Phys & Physicoinformat, Fac Sci & Technol, Kohoku Ku, Yokohama, Kanagawa 2238522, Japan

[3] Gunma Univ, Fac Engn, Dept Mat Engn, Kiryu, Gunma 3768515, Japan

来源：

PHYSICAL REVIEW B | 2007年 / 75卷 / 18期

关键词：

D O I：

10.1103/PhysRevB.75.184426

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

Evidence for ferromagnetism at the surface of a LaCoO3 single crystal is reported using a scanning superconducting quantum interference device (SQUID) microscope. Stray magnetic flux detected with the scanning SQUID shows typical ferromagnetic behavior in LaCoO3 below T-c similar to 85 K, in agreement with previous work on LaCoO3 particles. Analysis of the magnetization of LaCoO3 particle samples clearly shows that the magnetization is inversely proportional to the particle radius, giving the information that the ferromagnetism is restricted within a few unit cell layers from the surface. X-ray photoemission spectroscopy also indicates that the ferromagnetism likely originates from the metallic surface due to hole doping with oxygen chemisorption.

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页数：5

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