Effect of Ca doping on the Pr magnetic moment in Pr0.75Ca0.25MnO3.

We investigate the electronic structure of CMR manganite Pr1-xCaxMnO3 at x = 0 and 0.25, within density functional theory (DFT). We find that the Pr atoms in PrMnO3 do not posses any magnetic moment whereas in Pr0.75Ca0.25MnO3, the Pr moment changes to the high spin value of −1.95μB per formula unit. The appearance of the moment in Pr site, noticed experimentally long back, is an outstanding problem. Our ab initio electronic structure investigation leads us to the conclusion that the modified crystal ambience resulting from Ca doping holds the key to the origin of large Pr magnetic moment in Pr0.75Ca0.25MnO3. [ABSTRACT FROM AUTHOR]