An x-ray diffraction study of the temperature-induced structural phase transitions in SmVO3

TL;DR

This study uses powder and synchrotron x-ray diffraction to analyze the temperature-dependent structural phase transitions in SmVO3, revealing a single monoclinic phase below 200 K and magnetostriction effects below 134 K, with detailed structural refinements.

Contribution

It provides the first detailed structural analysis of SmVO3 across its phase diagram, clarifying its phase behavior and the role of Jahn-Teller distortion and magnetostriction.

Findings

SmVO3 remains monoclinic below 200 K, contrary to previous reports.

Magnetostriction stabilizes the monoclinic phase below 134 K.

Significant Jahn-Teller distortion correlates with G-type orbital order.

Abstract

Through powder x-ray diffraction we have investigated the structural behavior of SmVO3, in which orbital and magnetic degrees of freedom are believed to be closely coupled to the crystal lattice. We have found, contrary to previous reports, that SmVO3 exists in a single, monoclinic, phase below 200 K. The associated crystallographic distortion is then stabilized through the magnetostriction that occurs below 134 K. The crystal structure has been refined using synchrotron x-ray powder diffraction data measured throughout the structural phase diagram, showing a substantial Jahn-Teller distortion of the VO6 octahedra in the monoclinic phase, compatible with the expected G-type orbital order. Changes in the vanadium ion crystal field due to the structural and magnetic transitions have then been probed by resonant x-ray diffraction.