Abstract
A homogeneous powder sample of EuCu2P2 was synthesized from the elements by a two-step high-temperature ampule technique. X-ray powder diffraction analysis have shown that the compound belongs to the ThCr2Si2 structure type and features copper deficiency. The study of temperature changes of heat capacity, Cp(T) (2-300 K), and unit cell parameters, a(T) and c(T) and volume V-u(T) (5-300 K), ...
Abstract
A homogeneous powder sample of EuCu2P2 was synthesized from the elements by a two-step high-temperature ampule technique. X-ray powder diffraction analysis have shown that the compound belongs to the ThCr2Si2 structure type and features copper deficiency. The study of temperature changes of heat capacity, Cp(T) (2-300 K), and unit cell parameters, a(T) and c(T) and volume V-u(T) (5-300 K), revealed a pronounced anomaly at about T-Cmax = 44 K evidencing the phase transition to the ferromagnetic state. Detailed analyses of the extracted excess (magnetic) components of EuCu2P2 thermodynamic characteristics, C-m(T) and Delta(Vm)(T), have been performed using the Debye-Einstein and mean field theory approaches. We have found that the anomalous nature of C-m(T) and Delta(Vm)(T) at T < T-Cmax. is caused by the effect of the internal magnetic field on the magnetic moments of Eu2+ ions, and, to a lesser extent, by the splitting of the ground state of Eu2+ ions. Noticeable anisotropy of the EuCu2P2 thermal expansion at temperatures below TCmax as well as a significant effect of the anharmonicity of lattice vibrations on the thermal properties of EuCu2P2 at elevated temperatures have been documented. (c) 2020 Elsevier B.V. All rights reserved.
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