High-quality thin films of double perovskite La2NiMnO6 (LNMO) were epitaxially grown on Nb-doped SrTiO3 (NSTO) substrates by pulsed laser deposition. The films were found to undergo a ferromagnetic-to-paramagnetic transition at similar to 280 K, which is consistent with the literature report. In the electrical measurements, typical rectifying behavior was observed in the LNMO/NSTO heterojunction. The diffusion voltage (V-D) increases linearly with temperature (T) during cooling until T = 170 K. At T<170 K, V-D increases at a higher rate and the V-D-T relationship becomes non-linear. A disordered phase related spin polarization was used to understand such behaviors in the heterojunctions. (C) 2011 Elsevier B.V. All rights reserved.