Antiferromagnetism in Pr3In: Singlet/triplet physics with frustration

A. D. Christianson; J. M. Lawrence; J. L. Zarestky; H. Suzuki; J. D. Thompson; M. F. Hundley; J. L. Sarrao; C. H. Booth; D. Antonio; A. L. Cornelius

arXiv · cond-mat/0411493

Antiferromagnetism in Pr3In: Singlet/triplet physics with frustration

A. D. Christianson·J. M. Lawrence·J. L. Zarestky·H. Suzuki·J. D. Thompson·M. F. Hundley·J. L. Sarrao·C. H. Booth·D. Antonio·A. L. Cornelius

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Abstract

We present neutron diffraction, magnetic susceptibility and specific heat data for a single-crystal sample of the cubic (Cu3Au structure) compound Pr3In. This compound is believed to have a singlet (Gamma1) groundstate and a low-lying triplet (Gamma4) excited state. In addition, nearest-neighbor antiferromagnetic interactions are frustrated in this structure. Antiferromagnetic order occurs below T_N = 12K with propagation vector (0, 0, 0.5 +/-δ) where δ\approx 1/12. The neutron diffraction results can be approximated with the following model: ferromagnetic sheets from each of the three Pr sites alternate in sign along the propagation direction with a twelve-unit-cell square-wave modulation. The three moments of the unit cell of 1 μ_B magnitude are aligned so as to sum to zero as expected for nearest-neighbor antiferromagnetic interactions on a triangle. The magnetic susceptibility indicates that in addition to the antiferromagnetic transition at 12K, there is a transition near 70K below which there is a small (0.005 μ_B) ferromagnetic moment. There is considerable field and sample dependence to these transitions. The specific heat data show almost no anomaly at TN = 12K. This may be a consequence of the induced moment in the Gamma1 singlet, but may also be a sample-dependent effect.

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A. D. Christianson, J. M. Lawrence, J. L. Zarestky, H. Suzuki, J. D. Thompson, M. F. Hundley, J. L. Sarrao, C. H. Booth, D. Antonio, A. L. Cornelius. 2004-11-18. Antiferromagnetism in Pr3In: Singlet/triplet physics with frustration. https://arxiv.org/abs/cond-mat/0411493

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