Effects of Cr substitution on the magnetic and transport properties and electronic states of SrRuO3 epitaxial thin films

TL;DR

Cr substitution in SrRuO3 thin films enhances ferromagnetic transition temperature and modifies electronic states through orbital hybridization, also inducing low-temperature structural changes affecting transport properties.

Contribution

This study reveals how Cr substitution alters magnetic, electronic, and structural properties of SrRuO3 thin films, highlighting orbital hybridization effects and low-temperature phase transitions.

Findings

Increased ferromagnetic transition temperature with Cr doping

Orbital hybridization between Cr 3dt2g and Ru 4dt2g observed

Structural transition at low temperature affecting transport properties

Abstract

The effect of Cr substitution in a SrRuO3 epitaxial thin film on SrTiO3 substrate was investigated by measuring the magnetic and transport properties and the electronic states. The ferromagnetic transition temperature of the SrRu0.9Cr0.1O3 film (166 K) was higher than that of the SrRuO3 film (147 K). Resonant photoemission spectroscopy experimentally revealed that the Cr 3dt2g orbital is hybridized with the Ru 4dt2g orbital in the SrRu0.9Cr0.1O3 film, supporting the assumption that the enhancement of the ferromagnetic transition temperature through Cr substitution stems from the widening of energy bands due to the hybridization of Cr 3dt2g and Ru 4dt2g orbitals. Furthermore, we found that the Hall resistivity of the SrRu0.9Cr0.1O3 film at low temperature is not a linear function of magnetic field in the high-field region where the out-of-plane magnetization was saturated; this result suggests that the SrRu0.9Cr0.1O3 film undergoes a structural transition at low temperature accompanied with the modulation of the Fermi surface.