Magnetic coupling of stripe domains in FePt/Ni 80 Fe 20 bilayers

ÁLVAREZ, N R; GÓMEZ, J E; VÁSQUEZ MANSILLA, M; PIANCIOLA, B; ACTIS, D G; GILARDI, G J; LEIVA, L; MILANO, J; BUTERA, A

JOURNAL OF PHYSICS - D (APPLIED PHYSICS)

IOP PUBLISHING LTD

Año: 2017 vol. 50

0022-3727

Equiatomic FePt in the A1 soft magnetic phase and Ni80Fe20 (permalloy) thin films form astripe-like magnetic domain structure above a critical thickness. This critical thickness isconsiderably different in the two alloys and allows us to study the influence of the magneticcoupling in the domain configuration in bilayers. Using dc magnetron sputtering techniques,we fabricated two different sets of FePt/Ni80Fe20 bilayers, keeping one thickness fixed andvarying the other, and investigated the dc magnetic properties and the magnetic domainconfiguration of the structure. In all cases, magnetization reversal occurred at a single coercivefield, indicating a relatively strong magnetic exchange coupling between both layers. Theobserved stripe period was also consistent with a model of spring magnet-like behavior.However, for certain values of FePt and permalloy thickness a complex nonparallel doublestripe structure was found, which may be attributed to the influence of the dipolar stray field ofthe thicker layer on the stripe structure of the thinner film.