Observation of asymmetric Bloch walls in epitaxial Co films with strong in-plane uniaxial anisotropy

Combined studies involving magnetic force microscopy and micromagnetic simu lations are used to investigate the domain wall structure in epitaxial Co(1 0 (1) over bar0) thin films with strong in-plane uniaxial magneto-crystalli ne anisotropy. This letter shows experimental evidence that, for such a sys tem, the domain wall structure transforms from an asymmetric Bloch wall int o an asymmetric Neel wall upon decreasing the film thickness from 100 to 20 nm. This transition occurs without cross-tie wall formation. Furthermore, it is found that from the four possible energetically equivalent asymmetric Bloch wall configurations, only two are stabilized along a single domain w all. For a given wall, the transition from one configuration to the other i nvolves the simultaneous reversal of the polarity of the Bloch core and the Neel cap. <(C)> 2000 American Institute of Physics. [S0003-6951(00)03045-X ].