Long-Range Spin-Triplet Superconductivity Induced by Magnetic Field in d Wave Superconductor/Ferromagnet Hybrid System

We theoretically study the long-range spin- triplet superconductivity in d wave superconductor/ ferromagnet/ferromagnet (S/F-1/F-2) trilayer junction, in which the magnetization of F-1 layer could be rotated in the y-z plane by an external magnetic field. The four-component Eilenberger equations were constructed to calculate the superconducting order parameters and density of states (DOS). Near the clean limit, the p wave equal-spin triplet component could be induced when the magnetization directions of F-1/F-2 layers are non-collinear, and the DOS exhibits a split zero-bias conductance peak. The various parameters such as ferromagnetic exchange energy, thickness of ferromagnetic layers, and angles between F-1/F-2 magnetization directions are studied for the effect on inducing triplet superconductivity. By magnetic field controlling the emergence of equal-spin triplet pairings or not, such a tunable S/F-1/F-2 trilayer junction based on long-range spin-triplet superconductivity could be used as a superconducting switch device, which would open up a new view of spintronics.