  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.
