Influence of A-site cation size on structural and physical properties in Ca1-xSrxMn0.96Mo0.04O3:: A comparison of the x=0.3 and 0.6 compounds

Investigation of the electron-doped series Ca1-xSrxMn0.96Mo0.04O3 is reported. The magnetic, transport and structural properties have been characterized combining different techniques: X-ray diffraction, electron microscopy, magnetization. resistivity and thermopower measurements. For a constant small content of Mn+3 induced in the Mn+4 matrix by the Mo for Mn substitution, three crystallographic structures are evidenced, at room temperature, depending on the A-site size and the size mismatch effects. The influence of the structures on the transport and magnetic properties of these electron-doped manganites is presented. The optimization of the magnetoresistance and thermoelectric properties through the bandwidth parameter is presented. (c) 2005 Elsevier Inc. All rights reserved.