research Essay --

An intense research into the structural, physical and transport properties of perovskite manganites with the general formula of R1-xAxMnO3 (where R-rare earth element like La, Pr, Nd, Sm, and A - divalent element like Sr, Ca, Ba, and Pb) has been of recent interest due to colossal magnetoresistance (CMR) discovery[1-3].Attempts have been made to control the effective of one electron band width which primarily governs the magnetic and transport properties of the manganites through doping at the R and A sites[4-6]. In view of the complexity of the manganites, the knowledge on the relationship between the metal–insulator (MI) transition and ferromagnetic (FM)–paramagnetic (PM) transition in CMR manganite perovskites is ever increasing due to its potential applications [7-9]. The metallic properties of doped manganites such as La1-xSrxMnO3 (LSMO) with large band width are explained employing the double exchange (DE) theory [10-13]. It is inferred from the above studies that the narrow band width is not alone responsible for the observed MI transition and CMR in manganites like La1-xCaxM...