Enhancement of magnetoresistance in La0.67Ca0.33MnO3/Pr0.7Ca0.3MnO3 epitaxial multilayers

Multilayers of perovskite manganite oxides La0.67Ca0.33MnO3/Pr0.7Ca0.3MnO3,La0.67Ca0.33MnO3/LaMnO3 have been fabricated by pulsed laser deposition. Maganetoresistance (defining R(0)-R(H)/R(0)) of 98% has been observed in multilayers with Pr0.7Ca0.3MnO3 as the spacer layer. No enhancement is observed in multilayers with LaMnO3 as the spacer layer. Enhanced magnetoresistance in La0.67Ca0.33MnO3/Pr0.7Ca0.3MnO3 multilayers is explained on the basis of induced double exchange in the Pr0.7Ca0.3MnO3 layer as Mn exists both in 3+ and 4+ states. Such a facility does not exist in La0.67Ca0.33MnO3/LaMnO3 as Mn is present only in the 3+ state in LaMnO3. (C) 2001 Elsevier Science BY. All rights reserved.