Influence of disorder on the low and high temperature magnetization and magnetoresistance in Pr<inf>0.6</inf> R<inf>0.1</inf> Sr<inf>0.3</inf> MnO<inf>3</inf> (R = Tb, Y, Ho and Er) manganite

In this paper, we report the influence of the disorder on the magnetization and magnetoresistance in Pr0.6 R0.1 Sr0.3 MnO3 (R = Tb, Y, Ho and Er) manganites at high and low temperatures. At high temperatures, it is seen that both these properties are governed by the lowering of average A-site radii and increase in variance of the A-site disorder while at low temperatures by the rare earth ion coupling with that of Mn sublattice. The rare earth sublattice was found to order at a temperature very similar to that of corresponding rare earth manganate even though their concentrations were small. The magnetoresistance was found to scale with both the lowering of average A-site radii and increase in variance of the A-site disorder while at low temperatures was found to be independent of variance but rather depends on whether the dopant ion is magnetic or non magnetic. This behaviour was attributed to the competition that exists between double exchange and Jahn-Teller mechanisms which govern the physics of these systems. © 2006 Elsevier B.V. All rights reserved.