Crystal structure and magnetic properties of EuZrO3 solid solutions

Abstract

It is theoretically proposed that perovskite-type EuZrO₃ becomes a ferromagnet when the lattice volume is increased or the structure is changed from orthorhombic to cubic in contrast to the fact that the stable phase of EuZrO₃, the structure of which is orthorhombic, is antiferromagnetic. To investigate the change in crystal structure and magnetic properties of EuZrO₃ with the variation of lattice volume, we have synthesized polycrystals of solid solutions A_xEu_1−xZrO₃ (A = Ba, Ca, Sr); Eu²⁺ is substituted by group 2 elements with different ionic radius to realize the change in lattice volume and crystal structure of EuZrO₃. The stable magnetic structure of EuZrO₃ solid solutions is tuned with the change of lattice volume. In particular, the ferromagnetic state is stabilized by the increase in lattice volume, which experimentally verifies the prediction by the first-principles calculations. Furthermore, this phenomenon is explainable in terms of the competition between ferromagnetic and antiferromagnetic interactions that is highly related to the volume variation and the rotation of ZrO₆ octahedron. The present results indicate that the magnetic structure can be systematically tuned by controlling the chemical pressure in solid solutions.