We synthesized a quasi-two-dimensional distorted triangular lattice antiferromagnet Ca3CoNb2O9, in which the effective spin of Co2+ 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 θCW∼−55 K and the low Neel temperature(TN∼ 1.45 K) give a frustration factor f (=∣θCW/TN∣) ≈ 38, suggesting that Ca3CoNb2O9 resides in strong frustration regime. Slightly below TN, 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 Ms is suggested in the magnetization curve at 0.46 K. Our study indicates that Ca3CoNb2O9 is an interesting material to investigate magnetism in triangular lattice antiferromagnets with weak anisotropy.
@article{arxiv.1512.07792,
title = {Spin frustration and magnetic ordering in triangular lattice antiferromagnet Ca$_3$CoNb$_2$O$_9$},
author = {J. Dai and P. Zhou and P. S. Wang and F. Pang and T J. Munsie and G. M. Luke and J. S. Zhang and Weiqiang Yu},
journal= {arXiv preprint arXiv:1512.07792},
year = {2015}
}