Magnetization switching due to non-local spin injection into small ferromagnetic particle

In this paper, magnetic switching due to non-local spin injection into small ferromagnetic particle in a laterally ferromagnetic/nonmagnetic hybrid structure is investigated. Lateral multi-terminal spin-injection device is fabricated by means of the conventional lift-off technique. The device consists of two large Permalloy (Py) pads, a Cu cross and a Py small particle. Au wires are connected to the Py particle in order to reduce the total spin resistance of the Py particle. The non-local spin-valve signal is measured and is found to be 0.3 mΩ. This proves that the spin current from the Py pad is injected into the Py particle. Also, non-local spin injection into the Py particle is performed by applying the large pulsed current up to 15 mA. Results show that when the pulsed current is increased positively in the anti-parallel state, no signal is observed. On the other hand, increasing the pulsed current negatively reveals a change in the signal corresponding to the transition from the anti-parallel to parallel configurations at -13 mA. This implies that the magnetization in the Py particle is switched only by the spin current.