We report the magnetism and transport measurements of CaCo2As2 and Ca0.9Sr0.1Co2As2 single crystals. Antiferromagnetic transition was observed at about 70 K and 90 K for CaCo2As2 and Ca0.9Sr0.1Co2As2, respectively. Magnetism and magnetoresistance measurements reveal metamagnetic transition from an antiferromagnetic state to a ferromagnetic state with the critical field of 3.5 T and 1.5 T respectively along c-axis for these two materials at low temperature. For the field along ab-plane, spins can also be fully polarized above the field of 4.5 T for Ca0.9Sr0.1Co2As2. While for CaCo2As2, spins can not be fully polarized up to 7 T. We proposed the cobalt moments of these two materials should be ordered ferromagnetically within the ab-plane but antiferromagnetically along the c-axis(A-type AFM).
@article{arxiv.1204.1720,
title = {Metamagnetic transition in Ca$_{1-x}$Sr$_x$Co$_2$As$_2$($x$ = 0 and 0.1) single crystals},
author = {J. J. Ying and Y. J. Yan and A. F. Wang and Z. J. Xiang and P. Cheng and G. J. Ye and X. H. Chen},
journal= {arXiv preprint arXiv:1204.1720},
year = {2012}
}