Experimental and theoretical thermodynamic studies in Ba$_2$MgReO$_6$ -- the ground state in the context of Jahn-Teller effect

Jana Pásztorová; Aria Mansouri Tehrani; Ivica Živković; Nicola A. Spaldin; Henrik M. Rønnow

doi:10.1088/1361-648X/acc62a

paper

Experimental and theoretical thermodynamic studies in Ba $_{2}$ MgReO $_{6}$ -- the ground state in the context of Jahn-Teller effect

arXiv:2210.13616 · doi:10.1088/1361-648X/acc62a

Abstract

We address the degeneracy of the ground state multiplet on the 5 $d^{1}$ Re $^{6 +}$ ion in double perovskite Ba $_{2}$ MgReO $_{6}$ using a combination of specific heat measurements and density functional calculations. For Ba $_{2}$ MgReO $_{6}$ , two different ground state multiplets have previously been proposed - a quartet (with degeneracy $N$ =4) [1] and a doublet ( $N$ =2) [2]. Here we employ two independent methods for the estimation of phonon contribution in heat capacity data to obtain the magnetic entropy $S_{ma g}$ , which reflects the degeneracy of the ground state multiplet $N$ through $S_{ma g} = R$ ln $N$ . In both cases, we obtain a better fit to $S_{ma g} = R$ ln2 indicating evidence of $N$ =2 degeneracy in the range from 2 to 120~K. The detailed nature of the ground state multiplet in Ba $_{2}$ MgReO $_{6}$ remains an open question.

5 pages, 4 figures

Experimental and theoretical thermodynamic studies in Ba $_{2}$ MgReO $_{6}$ -- the ground state in the context of Jahn-Teller effect

Abstract

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Experimental and theoretical thermodynamic studies in Ba2​MgReO6​ -- the ground state in the context of Jahn-Teller effect

Abstract

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Cited by in corpus (5)

Experimental and theoretical thermodynamic studies in Ba $_{2}$ MgReO $_{6}$ -- the ground state in the context of Jahn-Teller effect