Weak Ferromagnetism in Fe1−xCoxSb2

Rongwei Hu1,2, R. P. Hermann3_, F. Grandjean3, Y. Lee4, J. B. Warren5, V. F. Mitrovi´c2 and C. Petrovic1

1Condensed Matter Physics, Brookhaven National Laboratory, Upton New York 11973-5000 USA

2Physics Department, Brown University, Providence RI 02912

3Department of Physics B5, Universit´e de Li`ege, Belgium

4Department of Earth System Sciences, Yonsei University, Seoul 120749, Korea

5Instrumentation Division, Brookhaven National Laboratory, Upton New York 11973-5000 USA

(Dated: February 2, 2008)

Weak ferromagnetism in Fe1−xCoxSb2 is studied by magnetization and M¨ossbauer measurements.

A small spontaneous magnetic moment of the order of _ 10−3μB appears along the bb-axis for 0.2 _

x _ 0.4. Based on the structural analysis, we argue against extrinsic sources of weak ferromagnetism.

We discuss our results in the framework of the nearly magnetic electronic structure of the parent

compound FeSb2.

PACS numbers: 75.30.-m, 76.80.+y, 71.28.+d