Nonlinear electrical transport via grain boundary tunneling in La-deficient compound La0.9Mn0.9Co0.1O3

Nonlinear electrical transport properties in La-deficient compound La0.9Mn0.9Co0.1O3 have been investigated as a function of temperature ( T ) and magnetic field ( H ) . The experiment was carried out through temperature range 20–293 K and in magnetic field up to 5 kOe. The nonlinear electrical transport was studied in low temperature region below the paramagnetic to ferromagnetic transition temperature ( T C ) at 195 K. The analysis of current–voltage ( I – V ) characteristic shows that the transport through grain boundary (GB) is dominated by multi-step inelastic tunneling in low temperature. This transport is also effected by magnetic field. Zero bias conductance [ G 0 = ( d I / d V ) V = 0 ] is enhanced in the presence of magnetic field. The electrical transport properties have been interpreted in terms of tunneling through the GB region where substitution of Mn by Co introduces more disorder in GB.