Room-temperature and low-field magnetoresistance of La-Sr-Mn-O thin films

Thin films of La0.71Sr0.29Mn1.01O3-delta have been sputtered onto polycryst alline YSZ, (110) sapphire, YSZ buffered Si and (100) SrTiO3 substrates. Mi crostructure and magnetotransport properties of these films are investigate d. Except for the epitaxial him on (100) SrTiO3 substrate, granular structu res with 20-100 nm grains in size are observed. In the granular films, resi stance changes about 0.5% within a field of 100 Oe are observed at room-tem perature. The resistivity and the hysteretic behavior of the magnetoresista nce are varied with substrate material. The low-field magnetoresistance is related to the microstructure and the magnetization process.