Nonlocal voltage effects in La2/3Ca1/3MnO3/La1/3Ca2/3MnO3/YBa2Cu3O7 trilayers

We consider nonlocal conductance effects in epitaxial trilayers made by ferromagnetic half-metal La2/3Ca1/3MnO3 and high T-c superconductor YBa2Cu3O7-delta separated by an insulating barrier of antiferromagnetic La1/3Ca2/3MnO3 with variable thickness. The Hall transresistance as a function of the barrier thickness and the applied magnetic field is measured to investigate the interplay between tunneling and frictional drag effects in ferromagnet/antiferromagnet/superconductor trilayers. The results show a subtle correlation between the tunneling and the drag to account for the observed decreasing of the transresistance as the barrier thickness and the magnetic field are varied. A phenomenological model addresses such features as an enhancement of the frictional drag when the process of tunneling gets suppressed.