Low temperature synthesis and magneto- electrical studies in Nd1−xPbxMnO3 system

The system Nd1 − xPb x MnO3 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 T P ∼ 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 T P . These results are supported by magnetic measurements over the observed temperature range. Resistivity data above T P 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.