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arXiv · 1408.3453

Magnetic phase diagram of Sr$_{1-x}$Ca$_x$Co$_2$P$_2$

J. Sugiyama·H. Nozaki·I. Umegaki·M. Harada·Y. Higuchi·E. J. Ansaldo·J. H. Brewer·M. Imai·C. Michioka·K. Yoshimura·M Månsson
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Abstract

In order to study the phase diagram from a microscopic viewpoint, we have measured wTF- and ZF-$\mu^+$SR spectra for the Sr$_{1-x}$Ca$_x$Co$_2$P$_2$ powder samples with $x=0$, 0.2, 0.4, 0.5, 0.6, 0.8, and 1. Due to a characteristic time window and spatial resolution of $\mu^+$SR, the obtained phase diagram was found to be rather different from that determined by magnetization measurements. That is, as $x$ increases from 0, a Pauli-paramagnetic phase is observed even at the lowest $T$ measured (1.8~K) until $x=0.4$, then, a spin-glass like phase appears at $0.5\leq x\leq0.6$, and then, a phase with wide field distribution probably due to incommensurate AF order is detected for $x=0.8$, and finally, a commensurate $A$-type AF ordered phase (for $x=1$) is stabilized below $T_{\rm N}\sim80~$K. Such change is most likely reasonable and connected to the shrink of the $c$-axis length with $x$, which naturally enhances the magnetic interaction between the two adjacent Co planes.

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J. Sugiyama, H. Nozaki, I. Umegaki, M. Harada, Y. Higuchi, E. J. Ansaldo, J. H. Brewer, M. Imai, C. Michioka, K. Yoshimura, M Månsson. 2014-08-15. Magnetic phase diagram of Sr$_{1-x}$Ca$_x$Co$_2$P$_2$. https://doi.org/10.1088/1742-6596/551/1/012010

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