Selective writing of sub-mu m(2) domain in spin valve strip with current coincident scheme

Cooperative nucleation of sub-mum(2) domains has been performed for a spin valve strip (0.4 mum width) of NiFe/Co/Cu/Co overlaid with orthogonal two-l ayer conductors (write and assist conductors). The current induced MR chang e due to the write current I-w markedly increases with the additional assis t current I-a. Threshold value of I-w, required for domain nucleation was d ecreased from 15 mA/mum to 9 mA/mum by the application of I-a with an ampli tude of 10 mA/mum, which confirms selective writing with the current coinci dent scheme. The cooperative effect disappears, when the phase difference b etween I-w and I-a becomes larger than the pulse width of 30 ns, Which can be associated with the fast relaxation time of the magnetization process in the sub-mum(2) region.