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The effect of lattice distortion and orbital mixing on the optical and magnetic properties of cubic RMnO$sub 3$ (R = La, Pr, Nd, Gd, Tb)

M. W. Kim·S. J. Moon·J. H. Jung·Jaejun Yu·Sachin Parashar·P. Murugavel·T. W. Noh
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Abstract

We investigated the $ab$-plane absorption spectra of $R$MnO$%_{3}$ ($R$ = La, Pr, Nd, Gd, and Tb) thin films. As the $R$-ion size decreases, we observed a drastic suppression of the 2 eV peak, \textit{i.e.} the inter-site optical transition between spin- and orbital-aligned states across the Mott gap. We found that both lattice distortion and the corresponding orbital mixing of the ordered orbital state should play an important role in the 2 eV peak suppression. We also found that the 2 eV spectral weight is proportional to the $A$-type antiferromagnetic ordering temperature, which suggests that the magnetic interaction might be sensitively coupled to the orbital mixing.

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M. W. Kim, S. J. Moon, J. H. Jung, Jaejun Yu, Sachin Parashar, P. Murugavel, T. W. Noh. 2005-04-25. The effect of lattice distortion and orbital mixing on the optical and magnetic properties of cubic RMnO$sub 3$ (R = La, Pr, Nd, Gd, Tb). https://arxiv.org/abs/cond-mat/0504616

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