The Tb Doping Effect on the Room Temperature Magnetoresistance in(La_1-xTb_x)_0.67Sr_0.33MnO₃（x≤0.4）

Hongwei QIN;Jifan HU;Juan CHEN;Hongdong NIU;Luming ZHU;Zhuo WANG Department of Physics,Shandong University Jinan 250100, China State Key Laboratory for Crystal Materials,Shandong University,Jinan 250100, China

摘 要：<正> With substitution of La by Tb in (La_1-xTb_x)_0.67Sr_0.33MnO₃, the room temperature magnetoresistance △R/R₀drops at first, then undergoes an increase near x≈0.1, and finally drops again. The value of room temperaturemagnetoresistance at a field H=12 kOe for (La_0.9Tb_0.1)_0.67Sr_0.33MnO₃ is -3.56%. The enhancement of the roomtemperature magnetoresistance induced by an appropriate Tb substitution in (La_1-xTb_x)_0.67Sr_0.33MnO₃ is correlatedwith the shifts of the Curie temperature and metal-insulator temperature to near room temperature. The drop ofthe room temperature magnetoresistance at large Tb doping-contents may be due to its lower T_C and T_MI far fromthe room temperature.

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