Bullk materials of two-element-doped manganite La0.67(Ca0.6Ba0.4)0.33MnOz (LCBMO) which were prepared by solid state reaction method, where shown to have cubic polycrystalline structure. The magnetic and colossal magnetoresistive properties of LCBMO were investigated and were compared with those of one-element-doped La0.67Ca0.33MnOz (LCMO) and La0.67Ba0.33MnOz (LBMO)prepared by the similar technique. The results showed that the Curie temperature (TC) of LCBMO was 312K, which was between those of LCMO and LBMO, and that the metal-semiconductor transition temperature (Tp) and magnetoresistance (MR) peak temperature (Tm) of LCBMO under μ0H=0.6T field were 306 and 298K respectively, both of which were close to its TC and were also between the Tp and Tm of LCMO and LBMO. Under μ0H=0.6T applied field, the colossal magnetoresistance value at corresponding Tm was 41% for LCMO, 24.7% for LCBMO, 8% for LBMO, but at room temperature (300K) the MR value of LCBMO still reached 20%, which was greatly larger than those of LCMO and LBMO, i.e.2.0% and 2.4%, respectively. It was observed that at low temperatures far below Tm there still existed magnetoresistance effect in LCMO, and the MR value of LCBMO and LBMO increased with decreasing temperature. These magnetoresistance properties at low temperatures could be ascribed to the intrinsic structural characterstics such as grain boundaries and density.
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