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Magnetic behavior of EuCu2As2: Delicate balance between antiferromagnetic and ferromagnetic order

Kausik Sengupta·P. L. Paulose·E. V. Sampathkumaran·Th. Doert·J. P. F. Jemetio
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Abstract

The Eu-based compound, EuCu2As2, crystallizing in the ThCr2Si2-type tetragonal structure, has been synthesized and its magnetic behavior has been investigated by magnetization (M), heat-capacity (C) and electrical resistivity (rho) measurements as a function of temperature (T) and magnetic field (H) as well as by 151Eu Moessbauer measurements. The results reveal that Eu is divalent ordering antiferromagnetically below 15 K in the absence of magnetic field, apparently with the formation of magnetic Brillouin-zone boundary gaps. A fascinating observation is made in a narrow temperature range before antiferromagnetism sets in: That is, there is a remarkable upturn just below 20 K in the plot of magnetic susceptibility versus T even at low fields, as though the compound actually tends to order ferromagnetically. There are corresponding anomalies in the magnetocaloric effect data as well. In addition, a small application of magnetic field (around 1 kOe at 1.8 K) in the antiferromagnetic state causes spin-reorientation effect. These results suggest that there is a close balance between antiferromagnetism and ferromagnetism in this compound

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Kausik Sengupta, P. L. Paulose, E. V. Sampathkumaran, Th. Doert, J. P. F. Jemetio. 2005-09-05. Magnetic behavior of EuCu2As2: Delicate balance between antiferromagnetic and ferromagnetic order. https://doi.org/10.1103/physrevb.72.184424

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