Low temperature synthesis and magnetoelectrical studies in Nd1−xPbxMnO3 system

The system Nd1−xPbxMnO3 with x ≤ 0.50 has been synthesized by citrate-gel route. All these samples have shown single phase structure with cubic symmetry. Magnetic and electrical behavior has been studied in the temperature range 4–300 K. The temperature dependent resistivity data shows that metal-semiconductor transitions occurs at temperature TP ∼ 166, 174 and 182 K for x = 0.30, 0.40 and 0.50 respectively. Under the field of 1 T , this transition shifts to higher temperature. These samples have shown maximum MR upto 40% under the field of 1 T at temperature lower than TP. These results are supported by magnetic measurements over the observed temperature range. Resistivity data above TP has been found to fit well with T n where n = −1/4 for x = 0.30 and n = −1/2 for x = 0.50 which is attributed to the variable range hopping of small polarons. C 2005 Springer Science + Business Media, Inc.