Exchange interaction effects on the optical properties of LuMnO3.
We have measured the optical conductivity of single crystal LuMnO3 from 10 to 45000 cm(-1) at temperatures between 4 and 300 K. A symmetry allowed on-site Mn d-d transition near 1.7 eV is observed to blueshift ( approximately 0.1 eV) in the antiferromagnetic state due to Mn-Mn superexchange interactions. Similar anomalies are observed in the temperature dependence of the TO phonon frequencies which arise from spin-phonon interaction. We find that the known anomaly in the temperature dependence of the quasistatic dielectric constant epsilon(0) below T(N) approximately 90 K is overwhelmingly dominated by the phonon contributions.
Souchkov
A B
AB
Materials Research Science and Engineering Center, University of Maryland, College Park, Maryland 20742, USA.
Simpson
J R
JR
Quijada
M
M
Ishibashi
H
H
Hur
N
N
Ahn
J S
JS
Cheong
S W
SW
Millis
A J
AJ
Drew
H D
HD