Observation of a bi-domain state and nucleation free switching in mesoscopic ring magnets.
We present the results of a study of the magnetic properties of an array of 34-nm thick Co(100) epitaxial ring magnets, with inner and outer diameters of d(in) = 1.3 microm and d(out) = 1.6 microm, respectively. Magnetic measurements and micromagnetic simulations show that a two step switching process occurs at high fields, indicating the existence of two different stable states. In addition to the vortex state, which occurs at intermediate fields, we have identified a new bi-domain state, which we term the onion state, corresponding to opposite circulation of the magnetization in each half of the ring. The onion state is stable at remanence and undergoes a simple and well characterized nucleation free switching.
Rothman
J
J
Cavendish Laboratory, University of Cambridge, United Kingdom.
Kläui
M
M
Lopez-Diaz
L
L
Vaz
C A
CA
Bleloch
A
A
Bland
J A
JA
Cui
Z
Z
Speaks
R
R