Magnetotransport Irreversibility in Single Crystalline La0.18Pr0.40Ca0.42MnO3 Thin Films

Abstract

Magnetotransport irreversibility in single crystalline La0.18Pr0.40Ca0.42MnO3 thin films is probed with respect to intrinsic electronic phase separation (IEPS). Temperature‐dependent magnetization and resistivity measurements show that (i) the high temperature non‐hysteretic regime is dominated by the antiferromagnetic insulator (AFMI) and the charge ordered (CO) phases; (ii) at intermediate temperatures hysteretic regime is akin to a spin liquid; and (iii) the glass transition occurs at temperature Tg below which the spin liquid freezes. The suppression of the ferromagnetic and insulator–metal transitions (TC and TIM) during cooling confirms supercooled magnetic liquid. Magnetic field‐dependent resistivity (ρ–H) measured during cooling and warming highlights the differences in the spin‐ordered structures through (i) reversible behavior at T < Tg; (ii) colossal irreversibility in the isothermal cooling and warming ρ–H at Tg < T < TC/TIM; and (iii) reversible ρ–H at low/moderate fields but irreversible behavior at high fields at T > TIM (warming). The present study demonstrates that the scaling of area between the isothermal cooling and warming cycle ρ–H curves with temperature mimics the ρ–T behavior and hence also reflects the insulator–metal transition. The observed irreversibility and the area scaling in the different spin regimes have been explained in terms of the intrinsic electronic phase separation.