Structural aspects of metamagnetism in Ca_{2-x}Sr_{x}RuO_4 (0.2 < x < 0.5): field tuning of orbital occupation

TL;DR

This study investigates how temperature and magnetic field influence the crystal structure and orbital occupation in Ca_{2-x}Sr_{x}RuO_4, revealing structural changes linked to metamagnetism.

Contribution

It provides detailed structural analysis showing field- and temperature-induced orbital rearrangements associated with metamagnetic transitions in Ca_{2-x}Sr_{x}RuO_4.

Findings

Structural shrinkage along c-axis below 25 K in zero field

Elongation in a, b planes upon cooling in zero field

Opposite structural changes occur at high magnetic fields

Abstract

The crystal structure of Ca_{2-x}Sr_xRuO_4 with 0.2 < x < 1.0 has been studied by diffraction techniques and by high resolution capacitance dilatometry as a function of temperature and magnetic field. Upon cooling in zero magnetic field below about 25 K the structure shrinks along the c-direction and elongates in the a, b planes (0.2 < x < 1.0), whereas the opposite occurs upon cooling at high-field (x = 0.2 and 0.5). These findings indicate an orbital rearrangement driven by temperature and magnetic field, which accompanies the metamagnetic transition in these compounds.