Signature of the Spin Triplet Phase in $La_{0.7}Sr_{0.3}MnO_3$/$Yba_2Cu_3O_7$/$La_{0.7}Sr_{0.3}MnO_3$ Trilayers

Differential dynamical subgap transport measurements were performed on LSMO/YBCO/LSMO trilayers to probe local evolution of the Andreev bound states which are manifested as the zero bias conductance peak. Dynamical conductivity dI/dV vs. magnetic field measured in current in plane and current perpendicular to plane geometries show nonmonotonic behavior with maximum at about 500 Oe. The shape of the zero bias conductance peak measured in current in plane geometry is sharp, whereas zero bias conductance peak measured in current perpendicular to plane geometry demonstrates V shape. These shapes of the zero bias conductance peak were predicted theoretically for unconventional p-wave spin triplet phase superconductor and superconductor with d-wave symmetry of the order parameter, respectively.