The suppression of magnetoresistance and superconductivity for La2/3Ca1/3MnO3/YBa2Cu3O<f>7−δ</f> bilayers

The La2/3Ca1/3MnO3 (LCMO, <f>tm=300</f> A˚)/YBa2Cu3O<f>7−δ</f> (YBCO, <f>ts=20</f>–500 A˚) heterostructural bilayers are prepared by the rf magnetic sputtering technique on SrTiO3 (STO) substrate at high temperature. Using the four-probe method, the electronic and magnetic transport properties have been investigated with and without magnetic field applied up to 4 T, The superconducting zero resistance temperature increases with the increase of the thickness of YBCO, <f>ts</f>, with <f>ts>85</f> A˚. The nature of resistance for LCMO is screened by YBCO with the thickness more than about 250 A˚, but the magnetoresistance (MR) effect is observed in the bilayers. MR increases with the decrease of the thickness of YBCO. Structural characterizations of the bilayers show that there is interdiffusion appeared in the interface between LCMO and YBCO, and, LCMO and STO. [Copyright &y& Elsevier]