A phenomenological description of the pressure sensitivity of the Curie temperature in hole-doped manganites

Abstract

We performed high pressure experiments on La0.8Ca0.2−xSrxMnO3 (LCSMO)(0 ≤ x ≤ 0.2) ceramic samples in order to analyze the validity of the well known relation between the A mean ionic radius ( rA ) 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 law that considers the systematic dependence of Tc with structural and electronic parameters. This law 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.

Doped Pr0.7−xBixSr0.3MnO3 manganite: A structural, electrical and magnetic effect

“…Recently Garbarino and Acah reported the chemical pressure (i.e. "A" site cation mismatch)/applied pressure effect on structural and electronic parameters in La 0.8 Ca 0.2−x Sr x MnO 3 ceramic manganite [11]. However manganites are not homogenous rather microscopic antiferromagnetic or paramagnetic inhomogeneity may present in ferromagnetic matrix as reported earlier by many authors [12][13][14][15].…”