Schematic diagram of a model system. Permalloy nanodisks of radius R and thickness L are used as model system and polarized current is applied via a point-contact represented by a white cylinder with radius R_c. Point-contact is located at y axis and its center distance from the disk center is d. Red arrow i p = 1 and blue arrow S p = − 1 refer to +z and −z directions of applied current and spin polarization, respectively.