Control of domain tip motion in a magnetic thin film

Abstract

The control of domain tip propagation in a narrow Permalloy thin film is presented. The control of domain tip motion consists of two parts. One is the control of the direction of tip propagation and the other is the uniform motion of a domain tip by successive pulse fields. To control the direction of tip propagation, the combination of two films with different coercive forces was used. If a magnetic field is applied to a narrow Permalloy film which has a hard film (large H <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</inf> ) on one end, a domain tip propagates along the channel. The direction of tip propagation depends on the direction of magnetization of the hard film. To control the uniform domain growth by a pulse field, a transverse ac magnetic field combined with a pulse field along the channel was used. An easy axis pulse field is 2 Oe, 30 ms, and a hard axis field is 1 kHz sinusoidal. A traveling length of a domain tip is proportional to a number of pulses applied along the easy axis. The traveling length per pulse is 0.53 mm at the hard axis field <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">H_{\perp} = 0.97</tex> Oe. The mechanism of this domain motion will be considered as a kind of creep.