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arXiv · 1807.04213

Tuning the orbital-lattice fluctuations in the mixed spin-dimer system Ba$_{3-x}$Sr$_{x}$Cr$_{2}$O$_{8}$

Alsu Gazizulina·Diana Lucia Quintero-Castro·Dirk Wulferding·Jeremie Teyssier·Karel Prokes·Fabiano Yokaichiya·Andreas Schilling
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Abstract

In $A_{3}$Cr$_{2}$O$_{8}$, where $A$ = Sr or Ba, the Cr$^{5+}$ ions surrounded by oxygen ions in a tetrahedral coordination are Jahn-Teller active. The Jahn-Teller distortion leads to a structural transition and a related emergence of three twinned monoclinic domains below the structural phase transition. This transition is highly dynamic over an extended temperature range for $A$ = Sr. We have investigated mixed compounds Ba$_{3-x}$Sr$_{x}$Cr$_{2}$O$_{8}$ with $x=2.9$ and $x=2.8$ by means of X-ray and neutron diffraction, Raman scattering and calorimetry. Based on the obtained evolution of the phonon frequencies, we find a distinct suppression of the orbital-lattice fluctuation regime with increasing Ba content. This stands in contrast to the linear behaviour exhibited by unit cell volumes, atomic positions and intradimer spin-spin exchange interactions.

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Alsu Gazizulina, Diana Lucia Quintero-Castro, Dirk Wulferding, Jeremie Teyssier, Karel Prokes, Fabiano Yokaichiya, Andreas Schilling. 2018-07-11. Tuning the orbital-lattice fluctuations in the mixed spin-dimer system Ba$_{3-x}$Sr$_{x}$Cr$_{2}$O$_{8}$. https://doi.org/10.1103/physrevb.98.144115

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