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Evidence for Multiple Phase Transitions in La_1-xCa_xCoO_3

M. Kriener·M. Braden·D. Senff·O. Zabara·T. Lorenz
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Abstract

We report thermal-expansion and specific-heat data of the series La_1-xCa_xCoO_3 for 0 <= x <= 0.3. For x = 0 the thermal-expansion coefficient alpha(T) features a pronounced maximum around T = 50 K caused by a temperature-dependent spin-state transition from a low-spin state (S=0) at low temperatures towards a higher spin state of the Co^3+ ions. The partial substitution of the La^3+ ions by divalent Ca^2+ ions causes drastic changes in the macroscopic properties of LaCoO_3. Around x ~ 0.125 the large maximum in alpha(T) has completely vanished. With further increasing x three different anomalies develop.

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M. Kriener, M. Braden, D. Senff, O. Zabara, T. Lorenz. 2006-05-30. Evidence for Multiple Phase Transitions in La_1-xCa_xCoO_3. https://doi.org/10.1016/j.jmmm.2006.10.529

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