Article ID Journal Published Year Pages File Type
1486429 Journal of Non-Crystalline Solids 2005 5 Pages PDF
Abstract

We report on a dielectric investigation of the glass-like freezing of the orbital reorientation-dynamics, recently found for the crystalline sulfo-spinels FeCr2S4 and FeSc2S4. As the orbital reorientations are coupled to a rearrangement of the surrounding ionic lattice via the Jahn–Teller effect, the freezing of the orbital moments is revealed by a relaxational behavior of the complex dielectric permittivity. Additional conductivity (both dc and ac) and contact contributions showing up in the spectra are taken into account by an equivalent circuit description. The orbital relaxation dynamics continuously slows down over six decades in time, before at the lowest temperatures the glass transition becomes suppressed by quantum tunnelling.

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Physical Sciences and Engineering Materials Science Ceramics and Composites
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