Anomalous Thermal Expansion in (Pr,Ca)MnO3 Due to Orbital Ordering

AbstractThe monoclinic lattice parameters of the perovskite manganites Pr1−x,CaxMnO3 were systematically measured by XRD at the Ca doping levels x = 0.4, 0.5 and 0.1 at temperatures from 83K to 403K. The orbital ordering transition observed around 250K at x = 0.4 and x = 0.5, located by SQUID magnetometry, was associated with a transient cell volume expansion of order 0.1%, during which the CO-related monoclinic distortion set in. The anomalous cell expansion, arguably driven by electrostructural disorder, was of sufficient magnitude to locally dominate the thermal expansion

Anomalous Thermal Expansion in (Pr,Ca)MnO3 due to Orbital Ordering

The monoclinic lattice parameters of the perovskite manganites Pr(1-x)CaxMnO3 were systematically measured by XRD at the Ca doping levels x=0.4, 0.5 and 0.1 at temperatures from 83 K to 403 K. The orbital ordering transition observed around 250 K at x=0.4 and x=0.5, located by SQUID magnetometry, was associated with a transient cell volume expansion of order 0.1%, during which the CO-related monoclinic distortion set in. The anomalous cell expansion, arguably driven by electrostructural disorder, was of sufficient magnitude to locally dominate the thermal expansion.</p