Electrical transport properties of heteroepitaxial p–np–n junction of charge-ordered La7/16Ca9/16MnO3 and 0.5 wt% Nb doped SrTiO3

Electrical transport properties of a heteroepitaxial p–np–n junction made of charge-ordered La7/16Ca9/16MnO3 (LCMO) and 0.5 wt% Nb doped SrTiO3 (SNTO) were studied. The junction displayed highly rectifying current–voltage characteristics over a temperature range from 85 to 280 K. The slope of the diffusion voltage vs temperature shows two evident changes, which can be respectively associated to the paramagnetic to ferromagnetic and ferromagnetic to antiferromagnetic (charge ordering ) magnetic transitions of LCMO. Two distinct electronic transport mechanisms are also discerned around the charge ordering temperature (TCO)(TCO); thermally assisted tunneling at temperatures lower than TCOTCO and diffusion/recombination at higher temperatures.