Micromagnetic calculation of spin wave propagation for magnetologic devices

The propagation of magnetic wave packets in magnetic nanowires was calculated as a function of wire width, field strength, field ramp time, field area size, and geometry of a magnetic nanowire. Spin waves are excited locally by applying a small perturbation in the magnetization in a 20 nm wide region. A wave packet is emitted from the input region and travels along the wire with a velocity of 740 m/s. The finite element micromagnetic simulations show that wave packets can be guided along a bent nanostructure without losses due to geometry; amplitude and frequency are exactly the same as in a straight wire with equal distance between excitation point and probe. The wave amplitude was found to decrease with increasing rise time of the excitation field with an upper limit of 100 ps. For a Permalloy wire with a thickness of 10 nm, the frequency peak changes from 10 GHz in a wire with 60 nm width to 6 GHz in a wire with 140 nm width. (c) 2008 American Institute of Physics.