Low temperature transport measurements on manganite thin films

We have performed low temperature transport measurements on a micro-fabricated multilayered manganite thin film structure down to 50 mK. The structure is composed of two thin films, a 26 nm-thick (La_0.4Pr_0.6)_0.67Ca_0.33MnO₃ (LPCMO) layer deposited on top of a 60 nm-thick La_0.67Ca_0.33MnO₃ (LCMO) layer grown on an (110) NdGaO₃ (NGO) substrate. The resistance of this structure is measured from two gold electrodes deposited on top of the LPCMO film with the exposed LPCMO layer etched out by ion plasma etching technique. We observed an upturn in the resistance below 30 K for various current excitations ranging from 0.2 to 100 μA. We report electric field dependence of the resistance of this structure.