Colossal magnetoresistance of Pr0.7Sr0.3MnO3 layer grown on charge-ordered La0.5Ca0.5MnO3 manganite layer

Abstract

We present a report of the interfacial reaction between ferromagnetic (FM) Pr0.7Sr0.3MnO3 (PSMO-3) in proximity to charge ordered (CO) La0.5Ca0.5MnO3 (LCMO-5) in a bilayer structure. PSMO-3/LCMO-5 bilayer film with high crystalline quality was epitaxially grown on SrTiO3 (001) substrate by pulsed laser deposition. The bilayer loses 20% of its resistance for only 0.5 T, and loses 50% of its resistance for 2 T. This large low-field magnetoresistance (LFMR) is comparable to some FM/CO multilayers and other mixed compounds including strongly competing phases. LFMR of ∼−73% has been achieved at H = 1 T and T = 185 K. The maximum MR reaches a value of ∼−641% at H = 9 T and T = 205 K and the corresponding MR at room temperature is ∼−30%. The formation of CO anti-ferromagnetic state in LCMO-5 and its collapse (melting) under the applied magnetic field may be responsible for the enhanced MR mentioned above. In other words, the enhancement of MR can be explained by a FM phase percolation. Moreover, exchange bias (EB) cannot be observed in the bilayer at low temperature of 3 K, further confirming the occurrence of FM phase percolation at the PSMO-3/LCMO-5 interface. The disappearance of EB can be explained by a combination of the preferable distribution of FM clusters and FM clusters percolation at the PSMO-3/LCMO-5 interface. Large MR can be realized by using a CO material as a sublayer, which can provide potential application in the used devices.