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Abstract La 0.7 Ca 0.3 Mn 0.95 M 0.05 O 3 (M = Mn, Al, 0.5Al+0.5In, and In) perovskites (AB O 3) were studied with x-ray diffraction and AC susceptibility measurements. We provide the phenomenological expressions for the electron bandwidth, W , and Curie temperature, T C , to describe the variance in these values caused by the change of the degree of doping in the A - position and of the type of dopant in the B -position. The observed decrease in T C with doping is found to be mostly related to the difference in the electron configuration of Mn3+ ions and dopant M , and partially caused by the change in the local crystal structure because of the difference in the Mn3+- and M- ion radii. [ABSTRACT FROM AUTHOR]

A complex analysis of the vacancy-doped Pr 1- x MnO 3+δ ( x = 0.0, 0.2) manganites is performed by x-ray diffraction, Raman and x-ray photoelectron spectroscopy, and magnetic measurements to study the features of electron, phonon and magnetic structure of the compounds. The x = 0.0 oxide belongs to orthorhombic Pnma structure, while the x = 0.2 exhibits pseudo cubic symmetry. Average valence of manganese for both samples is found to be ≈ 3.2 due to doping holes localized in the O 2 p states and the hybridization of Mn 3 d and O 2 p states. Observed unusually large intensity of the Raman mode at 650 cm −1 is assumed to be related to a high level of vacancies, while the vacancies suppress both the Jahn-Teller (485 cm −1 ) and charge-transfer d-d (610 cm −1 ) Raman modes. Griffiths-like singularity are firstly observed for the Pr 1- x MnO 3+δ manganites. The singularity is supposed to be originated from the vacancies and strain accommodation. [ABSTRACT FROM AUTHOR]