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Magnetic order in CaMn2Sb2 studied via powder neutron diffraction |
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| Authors: | C.A. Bridges V.V. Krishnamurthy S. Poulton M.P. Paranthaman B.C. Sales C. Myers S. Bobev |
| Affiliation: | a Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 6100, USA b NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899 8562, USA c Department of Materials Science and Engineering, University of Maryland, College Park, MD 20742, USA d Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 6056, USA e Department of Chemistry, University of Delaware, Newark, DE 19716, USA |
| Abstract: | This paper reports a neutron powder diffraction study of CaMn2Sb2 in the temperature range of 20–300 K. Collinear long-range antiferromagnetic order of manganese ions occurs below 85 K, where a transition is observed in the dc magnetic susceptibility measured with a single crystal. Short-range magnetic order, characterized by a broad diffraction peak corresponding to a d-spacing of approximately 4 Å (2θ≈22°), is also observed above 20 K. The long-range antiferromagnetic order is indexed by the chemical unit cell, indicating a propagation vector k=(0 0 0), with a refined magnetic moment of 3.38 μB at 20 K. Two possible magnetic models have been identified, which differ in spin orientation for the two manganese ions with respect to the ab plane. The model with spins oriented at a 25±2° angle relative to the ab plane gives an improved fit compared to the other model in which the spins are constrained to the ab plane. Representational analysis can account for a model involving a c-axis component only by the mixing of two irreducible representations. |
| Keywords: | Polar Intermetallic Magnetic structure Representational analysis Antiferromagnet Neutron diffraction |
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