Uniaxial strain control of bulk ferromagnetism in rare-earth titanates

TL;DR

This study demonstrates that uniaxial strain can reversibly and continuously control ferromagnetism in rare-earth titanates by tuning structural distortions, supported by experimental measurements and ab initio calculations.

Contribution

It provides the first direct experimental evidence that uniaxial strain can tune ferromagnetism in rare-earth titanates through structural distortions, supported by theoretical modeling.

Findings

Reversible control of Curie temperature with strain

Agreement between experimental data and ab initio calculations

Potential for tuning magnetic phases in quantum materials

Abstract

The perovskite rare-earth titanates are model Mott insulators with magnetic ground states that are very sensitive to structural distortions. These distortions couple strongly to the orbital degrees of freedom and, in principle, it should be possible to tune the superexchange and the magnetic transition with strain. We investigate the representative system (Y,La,Ca)TiO$_3$, which exhibits low crystallographic symmetry and no structural instabilities. From magnetic susceptibility measurements of the Curie temperature, we demonstrate direct, reversible and continuous control of ferromagnetism by influencing the TiO$_6$ octahedral tilts and rotations with uniaxial strain. The relative change in $T_C$ as a function of strain is well described by ab initio calculations, which provides detailed understanding of the complex interactions among structural, orbital and magnetic properties in rare-earth titanates. The demonstrated manipulation of octahedral distortions opens up far-reaching possibilities for investigations of electron-lattice coupling, competing ground states, and magnetic quantum phase transitions in a wide range of quantum materials.