Electroresistance and magnetoresistance effects in superconductor-insulator-ferromagnet hybrid structures

We investigated superconducting YBa2Cu3O7 (YBCO), insulator SrTiO3 (STO), and ferromagnetic La2/3Ca1/3MnO3 (LCMO) multilayered heterostructures grown by pulsed laser deposition (PLD) on 〈1 0 0〉 YSZ substrates. These hybrid structures have demonstrated strong superconducting properties, similar to those of YBCO films, with a minimum influence of the ferromagnetic layer. We report unusual transport properties and negative differential resistance above the superconducting transition. The electro- and magnetoresistance effects observed in a hybrid YBCO micro-bridge with a top LCMO layer may be the consequence of phase separation induced by electric current.