Effect of A-site deficiency on electrical transport properties of YSZ doped manganites

The. electrical transport properties of the composite samples: A-site stoichiometry (1-x)La2/3Ca1/3MnO3 + xYSZ and A-site deficiency (1-x)(La2/3Ca1/3)(0.95)MnO3 + xYSZ with different YSZ percentage x were investigated, respectively. The similar metal-insulator transition at different temperature T-P was observed in the two types of composite samples: With increasing of the YSZ percentage, the zero-field resistivity of the composite samples increases and T-P shifts to the low temperature for the range of x < 2%, but zero-field resistivity decreases and T-P increases for the range of x > 2%. For the same YSZ percentage x, T-P of (1-x)La2/3Ca1/3MnO3 + xYSZ is lower than that of (1-x)(La2/3Ca1/3)(0.95)MnO3 + xYSZ. The different effects between the two type composites were also observed in the nonlinear current-voltage (I-V) behaviors. The results suggest that A-site deficiency and YSZ dopant can be used to adjust purposely the metal-insulator transition temperature and resistivity of composites. (C) 2002 Elsevier Science Ltd. All rights reserved.