Magnetic Specific Heat of Pb 1-x Eu x Te
M. Górska a , A. Łusakowski a , A. Jędrzejczak a , Z. Gołacki a , J.R. Anderson b and H. Balci b
a Institute of Physics, Polish Academy of Sciences al. Lotników 32/46, 02-668 Warszawa, Poland
b Department of Physics, University of Maryland, College Park, MD 20742, USA
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The temperature dependence of the magnetic specific heat was studied experimentally and theoretically in the semimagnetic semiconductor Pb 1-x Eu x Te for x=0.027 and x=0.073, over the temperature range from 0.5K to 15K, in magnetic fields up to 2T. In zero magnetic field at about 2K there was a broad maximum in the magnetic specific heat, which was much higher than that predicted by the model of superexchange interaction between nearest neighbors; the maximum values increased with magnetic field. The experimental data were analyzed in the framework of a model which takes into account the spin splitting of the ground state of a single Eu 2+ ion in the presence of local lattice distortions in the Pb 1-x Eu x Te mixed crystal. The model describes well the experimental data, especially for lower x-values, where the contribution from singlets dominates.
DOI: 10.12693/APhysPolA.105.631
PACS numbers: 71.70.--d, 75.40.Cx