Substrate effect on low‐field transport properties of La–Pb–Mn–O granular‐type thin films

This paper studied the low‐field tunnel‐type transport characteristics of polycrystalline and c ‐axis‐oriented La 0.7 Pb 0.3 MnO 3 (LPMO) thin films. Polycrystalline thin films were fabricated on SiO 2 /Si(100) substrate (film A), on SiO 2 /Si substrate with yttria‐stabilized zirconia (YSZ) buffer layer (film B), and on c ‐axis‐oriented thin film grown on LaAlO 3 (001) (LAO) single crystal substrate (film C) using the soft‐chemical deposition method. A YSZ buffer layer acts as a barrier against inter‐diffusion. As a result, it decreases the amount of dead layers generated from the interface and helps to produce qualitative films for application of magnetoresistive elements. The magnetoresistance (MR) ratio was 0.52%, 0.7%, and 0.4% for film A, film B, and film C under the applied field of 500 Oe at 300 K, respectively. The polycrystalline film had denser boundaries than the c ‐axis oriented film, i.e., the polycrystalline film gave more effective potential barrier regions than the c ‐axis oriented film. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)