Impact of magnetic phase coexistence on magnetotransport in polycrystalline Nd0.51Sr0.49MnO3 thin film

Abstract

We report the magnetic and transport properties of Nd0.51Sr0.49MnO3 polycrystalline thin films (thickness ∼ 100 nm) prepared by dc magnetron sputtering on single crystal Y-stabilized ZrO2(1 0 0) substrates. The paramagnetic (PM) to ferromagnetic (FM) transition at TC = 260 K is followed by A-type antiferromagnetic (AFM) ordering at and charge ordered (CO) phase having the CE type spin order at . The strong CO-AFM transition observed at TCO ∼ 150 K at half doping is softened by a small increase in the Nd concentration and the disorder due to the polycrystalline nature of these films. The multiple magnetic transitions are suggestive of strong phase coexistence. In this study the insulator-like to metal-like transition temperature TIM ∼ 140 K is considerably lower than the TC and remains independent of the external magnetic field up to 70 kOe. This suggests that electrical transport is dominated by grain boundaries and has percolation type characteristics due to the existence of metallic (FM + A-AFM) and insulating (CO-AFM + GB) paths. The films show large magnetoresistance at low as well as high magnetic fields.