Electrical Transport and Low-Field Magnetoresistance in La_2/3Ca_1/3MnO₃/YSZ Composites

Electrical transport and low-field magnetoresistance (MR) are
reported for (1-x)LCMO/xYSZ composites (0 < x < 80%)(LCMO = La_2/3Ca_1/3MnO₂ and YSZ being yttria stabilized zirconia). Different transport and MR behaviour are observed for x < 2% and x > 2%. In particular, the composite with x ≤ 1% shows a wide temperature window with a large constant MR below the transition. Based on the microscopy analysis, a possible interpretation is presented for different observations for x < 2% and x > 2% with emphasis on the boundary effect arising from insulating YSZ layers.