Features of EuFe2As2 Magnetic Structure Revealed by ESR.

Magnetic state of the EuFe 2 As 2 single crystal was investigated by electron spin resonance (ESR). The ESR spectra of europium ions were registered in the temperature range from 250 to 4 K. To study the anisotropy, the in-plane angular dependences were investigated at temperatures of 15 K upon rotating a crystal around the c-axis. The data analysis shows that EuFe 2 As 2 is an antiferromagnet with an easy anisotropy plane. Moreover, the second-order easy magnetization axis is observed for each of the two types of magnetic domains related with structural twins arising from the tetragonal-to-orthorhombic crystal lattice transition. [ABSTRACT FROM AUTHOR]