The Sr content influence on the positive magnetoresistance in La1−xSrxMnO3/Si heterojunctions

Yang Fang, Jin Kui-Juan, Huang Yan-Hong, He Meng, Lü Hui-Bin, Yang Guo-Zhen
2010 Chinese Physics B  
We fabricated La 1−x SrxMnO 3 /Si (LSMO/Si) heterojunctions with different Sr doping concentrations (x = 0.1, 0.2, 0.3) in LSMO and studied the Sr content influence on magnetoresistance (MR) ratio. The heterojunctions show positive MR and high sensitivity of MR ratio in a low applied magnetic field. The MR ratio is dependent on Sr content and the low Sr doping in LSMO causes a large positive MR in LSMO/Si junctions. The MR ratio for 0.1 Sr doping in the LSMO/Si heterostructure is 116% in 100 Oe
more » ... e is 116% in 100 Oe (1 Oe=79.5775 A/m) at 210 K. The mechanism for the positive MR dependence on the doping density is considered to be the competition between the tunneling rate of electrons in e 1 g ↑ to t 2g ↓ band and that to e 2 g ↑ band at the interface region of LSMO. The experimental results are in agreement with those observed in La 0.9 Sr 0.1 MnO 3 /SrNb 0.01 Ti 0.99 O 3 p-n junction. The results indicate that choosing low doping concentration to improve the low field sensitivity of the heterojunction devices is a very efficacious method.
doi:10.1088/1674-1056/19/8/087301 fatcat:kmozf4chbzetfnq72ghccaan24