A phenomenological description of the pressure sensitivity of the Curie temperature in hole-doped manganitesG. Garbarino and C. Acha
Laboratorio de Bajas Temperaturas, Departamento de Física, FCEyN, Universidad Nacional de Buenos Aires Pabellón I, Ciudad Universitaria, C1428EHA Buenos Aires, Argentina
received 3 June 2009; accepted in final form 26 October 2009; published November 2009
published online 2 December 2009
We performed high-pressure experiments in La0.8Ca0.2-xSrxMnO3 (LCSMO)(0x0.2) ceramic samples in order to analyze the validity of the well-known relation between the A-cation mean ionic radius and the Curie temperature Tc of hole-doped manganites at a fixed doping level and for doping values below the 0.3 (Mn+4/Mn+3) ratio. By considering our results and collecting others from the literature, we were able to propose a phenomenological relation that considers the systematic dependence of Tc with structural and electronic parameters. The proposed expression predicts fairly well the pressure sensitivity of Tc, its dependence with the A-cation radius disorder and its evolution in the high-pressure range. Considering a Double-Exchange model, modified by polaronic effects, the phenomenological law obtained for Tc can be associated with the product of two terms: the polaronic modified bandwidth and an effective hole doping.
62.50.-p - High-pressure effects in solids and liquids.
71.30.+h - Metal-insulator transitions and other electronic transitions.
75.47.Lx - Manganites.
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