Effect of substrate dependence on microstructure and magnetoresistance of lanthanum manganite films

The effect of buffered substrates on microstructure and magnetoresistive property of polycrystalline lanthanum manganite films is reported. By electron microscopy observation, the microstructure of the lanthanum manganite films is strongly influenced by buffer layers. Stresses arising during post annealing and/or due to the large lattice mismatch in the films were relaxed by forming defect structures in the films. The large negative magnetoresistance effect is demonstrated. The low field magnetoresistances of about 8–12% at an external field of 2 KOe were obtained.