Negative differential resistance in La0.67Ca0.33MnO3−δ∕Nb–SrTiO3 p-n junction

La0.67Ca0.33MnO3−δ∕Nb–SrTiO3 p-n junction was fabricated by pulsed laser deposition. The I-V curves of this junction show rectifying behavior. Negative differential resistance (NDR) was observed at low temperatures under large bias voltages and NDR becomes more remarkable with decreasing temperature. In addition to NDR, the I-V curves also show remarkable hysteresis. The results were explained in terms of the effect of local Joule heating on the phase separation in the strained ultrathin La0.67Ca0.33MnO3−δ thin film.