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arXiv · 1512.07792

Spin frustration and magnetic ordering in triangular lattice antiferromagnet Ca$_3$CoNb$_2$O$_9$

J. Dai·P. Zhou·P. S. Wang·F. Pang·T J. Munsie·G. M. Luke·J. S. Zhang·Weiqiang Yu
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Abstract

We synthesized a quasi-two-dimensional distorted triangular lattice antiferromagnet Ca$_3$CoNb$_2$O$_9$, in which the effective spin of Co$^{2+}$ is 1/2 at low temperatures, whose magnetic properties were studied by dc susceptibility and magnetization techniques. The x-ray diffraction confirms the quality of our powder samples. The large Weiss constant $\theta_{CW}\sim$ $-55$ K and the low Neel temperature($T_N\sim$ 1.45 K) give a frustration factor $f$ ($=\mid\theta_{CW}/T_N \mid$) $\approx$ 38, suggesting that Ca$_3$CoNb$_2$O$_9$ resides in strong frustration regime. Slightly below $T_N$, deviation between the susceptibility data under zero-field cooling (ZFC) and field cooling (FC) is observed. A new magnetic state with 1/3 of the saturate magnetization $M_s$ is suggested in the magnetization curve at 0.46 K. Our study indicates that Ca$_3$CoNb$_2$O$_9$ is an interesting material to investigate magnetism in triangular lattice antiferromagnets with weak anisotropy.

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J. Dai, P. Zhou, P. S. Wang, F. Pang, T J. Munsie, G. M. Luke, J. S. Zhang, Weiqiang Yu. 2015-12-24. Spin frustration and magnetic ordering in triangular lattice antiferromagnet Ca$_3$CoNb$_2$O$_9$. https://doi.org/10.1088/1674-1056%2F24%2F12%2F127508

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