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Ultrasonic evidence of an uncorrelated cluster formation temperature in manganites with first-order magnetic transition at T_C

J. Mira·J. Rivas·A. Moreno-Gobbi·M. Perez-Macho·F. Rivadulla
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Abstract

Ultrasonic attenuation and phase velocity measurements have been carried out in the ferromagnetic perovskites La_{2/3}Ca_{1/3}MnO_3 and La_{2/3}Sr_{1/3}MnO_3. Data show that the transition at the Curie temperature, T_C, changes from first- to second-order as Sr replaces Ca in the perovskite. The compound with first-order transition shows also another transition at a temperature T* > T_C. We interpret the temperature window T_C < T < T* as a region of coexistence of a phase separated regime of metallic and insulating regions, in the line of recent theoretical proposals.

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J. Mira, J. Rivas, A. Moreno-Gobbi, M. Perez-Macho, F. Rivadulla. 2003-04-08. Ultrasonic evidence of an uncorrelated cluster formation temperature in manganites with first-order magnetic transition at T_C. https://doi.org/10.1103/physrevb.68.092404

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