Current-induced magnetoresistance avalanche in

We show that magnetic field ( H ) dependence of resistivity ( ρ ) in Nd0.5Ca0.5Mn0.95Ni0.05O3 shows unusual features with increasing amplitude of the dc current ( I ) in the sample. While ρ ( H ) at T = 40 K decreases smoothly with increasing H and exhibits irreversibility with field cycling for current amplitudes less than 1 mA, an avalanche like decrease occurs at a critical value of H for I > 5 mA. The critical field increases with increasing amplitude of the dc current and the ρ ( H ) exhibits a reversible hysteresis in the complete field cycle at higher dc current strengths. It is shown that the avalanche in ρ is accompanied by an abrupt decrease in the temperature of the sample ( Δ T = 47 K ) which underscores the importance of magnetothermal coupling in the current-induced magnetoresistance avalanche.