Interaction between magnetism and superconductivity in La$_{0.7}$Ca$_{0.3}$MnO$_3$/YBa$_2$Cu$_3$O$_{7-\delta}$ multilayers

Angular and field dependent magnetoresistance measurements were performed on La$_{0.7}$Ca$_{0.3}$MnO$_3$/YBa$_2$Cu$_3$O$_{7-\delta}$ (LCMO/YBCO) heterostructures below and above the superconducting transition temperature $T_{c} \approx$ 28 K of the YBCO layer, in order to address the origin of the long range proximity effect found in these heterostructures. The proximity-induced conductance in the LCMO layer at $T