PII: S0921-4526(97)00321-9
Investigation of domain-wall formation and motion in magnetic multilayers L. H. Bennetta, b, *, M. J. Donahueb, A. J. Shapirob, H. J. Brownb, V. S. Gornakovb, c and V. I. Nikitenkob, c a Institute for Magnetics Research, The George Washington University Ashburn, VA 20147-2604 USAb National Institute of Standards and Technology Gaithersburg, MD 20899 USAc Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka Moscow District, 142432 Russian Federation Available online 16 May 1998.
L. H. Bennetta, b, *, M. J. Donahueb, A. J. Shapirob, H. J. Brownb, V. S. Gornakovb, c and V. I. Nikitenkob, c
The magnetization-reversal processes in two electrodeposited [Co64Ni31Cu5 2 nm/Cu]200 multilayers are investigated using an advanced magneto-optical indicator film (MOIF) technique together with SQUID and vector vibrating sample magnetometry. The non-magnetic Cu spacers are 1 nm thick in one specimen leading to predominantly antiferromagnetic exchange coupling between the ferromagnetic Co64Ni31Cu5 layers, and 3 nm in the other, with ferromagnetic coupling. The hysteresis loop of the ferromagnetic multilayer is conventional, indicating the stages of domain-wall formation, motion and saturation. Nucleation and movement of domain walls in different layers proceed in a partially uncorrelated manner, and are determined by defects near the surface edge and inside of the multilayer. As a result, the front of the magnetization reversal has a staggered configuration. The antiferromagnetic multilayer has an atypical loop, first with one susceptibility, then a step to a new value, then another susceptibility, and with non-symmetrical behavior about the field axis. Narrow and non-staggered domain-wall images in antiferromagnetically coupled layers are observed. The MOIF technique is used to provide a portrait of the vertical component of the magnetostatic field intensity, helping to elucidate the spin-flip and/or spin-flop processes which are apparently responsible for the hysteresis behavior.
Author Keywords: Magnetic multilayers; Magnetization reversal process; Antiferromagnetism; Magnetic-optical detection; Magnetic domains; Spin-flop process; Domain-wall motion
Index Terms: Magnetic materials; Multilayers; Magnetoresistance; Magnetic domains; Magnetization; Magnetic hysteresis; Crystal defects; Magnetic permeability; Magnetostatics; Copper; Cobalt; Nickel; Magnetic field measurement; Magnetic multilayers; Magnetization reversal; Magnetic optical detection; Spin flop process; Domain wall motion
*Corresponding author.
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