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With substitution of La by Tb in (La_(1-x)Tb_x)_(0.67)Sr_(0.33)MnO_3, the room temperature magnetoresistance △R/R_0drops 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_(0.9)Tb_(0.1))_(0.67)Sr_(0.33)MnO_3 is -3.56%. The enhancement of the roomtemperature magnetoresistance induced by an appropriate Tb substitution in (La_(1-x)Tb_x)_(0.67)Sr_(0.33)MnO_3 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.
With substitution of La by Tb in (La_ (1-x) Tb_x) _ (0.67) Sr_ (0.33) MnO_3, the room temperature magnetoresistance ΔR / R_0drops 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_ (0.9) Tb_ (0.1)) _ (0.67) Sr_ (0.33) MnO_3 is -3.56%. The enhancement of the roomtemperature magnetoresistance induced by an appropriate Tb substitution in (La_ (1-x) Tb_x) _ (0.67) Sr_ (0.33) MnO_3 is correlated with the shifts of the Curie temperature and metal-insulator temperature to near room temperature. The drop of the room temperature magnetoresistance at large Tb doping-contents may be due to its lower T_C and T_ (MI) far from the room temperature.