Fast Resistance Relaxation in Nanostructured La–Ca–Mn–O Films in Pulsed Magnetic Fields

The results of fast resistance relaxation of nanostructured La_1-xCa_xMnO₃ (LCMO) films with different compositions x (0.218, 0.285, 0.296, 0.41) grown by the metal-organic chemical vapor deposition technique are presented. The fast (~200 μs) resistance relaxation process observed after the magnetic field pulse was switched off was studied in pulsed fields up to 14 T in the temperature range of 80-170 K. It was found that the remnant resistivity of the fast relaxation process is proportional to the magnetoresistance of the films up to 10 T. The smallest remnant relaxation values were found for the films with highest insulator-metal transition temperature T_m. It was shown that the fast process could be analyzed using the Kolmogorov-Avrami-Fatuzzo model, taking into account the reorientation of magnetic domains into their equilibrium state. It was concluded that LCMO films with x=0.218 should be favored for the development of fast pulsed magnetic field sensors operating at cryogenic temperatures.