摘要
We fabricated La1-xSrxMnO3/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 （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 eg^1↑ to t2g↓ band and that to eg^2 ↑ band at the interface region of LSMO. The experimental results are in agreement with those observed in La0.9Sr0.1MnO3/SrNb0.01Ti0.99O3 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.
We fabricated La1-xSrxMnO3/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 （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 eg^1↑ to t2g↓ band and that to eg^2 ↑ band at the interface region of LSMO. The experimental results are in agreement with those observed in La0.9Sr0.1MnO3/SrNb0.01Ti0.99O3 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.
基金
Project supported by the National Natural Science Foundation of China(Grant No.50672120)
