Magnetization reversal in sputtered Co and oxidized Co (CoOx) layers an stu
died using transport measurements and magneto-optic Kerr effect. When assoc
iated in a magnetic tunnel junction, the two magnetic layers show a strong
ferromagnetic coupling. Using the tunnel magnetoresistive effect as a probe
for micromagnetic studies, we show the existence of an unexpected domain s
tructure in the soft Co layer. This domain structure originates from the du
plication of the domain structure of the hard CoOx magnetic layer template
into the soft Co layer via the ferromagnetic coupling.