Colossal magnetoresistance in screen printed La0.67Ca0.33MnO3 thick films

Thick films of La0.67Ca0.33MnO3 were fabricated on (100) oriented single crystal LaAlO3 (LAO), yttria stabilized zirconia (YSZ) and on polycrystalline Al2O3 by a screen printing technique. A range of sintering conditions were explored with temperature of 1200, 1300 and 1400°C, and in air, oxygen and nitrogen atmospheres. Magnetic and DC resistance properties were measured on all films. The so-called ‘colossal magnetoresistance’ (CMR) behaviour was found to occur for films on all substrates but for specific preparation conditions. The salient feature of the CMR observed in these thick films is that MR is not limited to a small temperature window near the metal–insulator transition (M–I), Tp1. The MR peak is very broad and for some films a temperature independent CMR is observed at temperatures below Tp1. Several repeat films were made and the reproducibility of the results obtained in the first batch was confirmed.