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

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.

4 pages, 2 figures

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Cited by in corpus (2)

• Magnetic field-dependent dielectric constant in La2/3Ca1/3MnO3
• Influence of magnetic field on paramagnetic-ferromagnetic transition in La${}_{1-x}$Ca${}_x$MnO${}_3$ ($x\approx 0.25$) crystal: ultrasonic and transport studies