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Evidence for Jahn-Teller distortions at the antiferromagnetic transition in LaTiO$_3$

J. Hemberger·H. -A. Krug von Nidda·V. Fritsch·J. Deisenhofer·S. Lobina·T. Rudolf·P. Lunkenheimer·F. Lichtenberg·A. Loidl·D. Bruns·B. Büchner
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Abstract

LaTiO$_3$ is known as Mott-insulator which orders antiferromagnetically at $T_{\rm N}=146$ K. We report on results of thermal expansion and temperature dependent x-ray diffraction together with measurements of the heat capacity, electrical transport measurements, and optical spectroscopy in untwinned single crystals. At $T_{\rm N}$ significant structural changes appear, which are volume conserving. Concomitant anomalies are also observed in the dc-resistivity, in bulk modulus, and optical reflectivity spectra. We interpret these experimental observations as evidence of orbital order.

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J. Hemberger, H. -A. Krug von Nidda, V. Fritsch, J. Deisenhofer, S. Lobina, T. Rudolf, P. Lunkenheimer, F. Lichtenberg, A. Loidl, D. Bruns, B. Büchner. 2003-08-07. Evidence for Jahn-Teller distortions at the antiferromagnetic transition in LaTiO$_3$. https://doi.org/10.1103/physrevlett.91.066403

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