Magnetic switching in 100 nm patterned pseudo spin valves

Progress in developing operative high-density magnetoresistive random acces s memory (MRAM) devices relies critically on tailoring the magnetic switchi ng occurring in arrays of small patterned pseudo spin valve (PSV) elements. Co/Cu/NiFe PSV films, produced by sputtering in the presence of a magnetic field, have an in-plane anisotropy and switching fields of typically 10 Oe for the soft NiFe and 40 Oe for the hard Co. These films were patterned in to arrays of elliptical and circular elements with dimensions of 80 nm to 1 0 mum. The layered structure in these large-area arrays of compositionally modulated PSV elements is preserved through the patterning processes. Hyste resis measurements of the dot arrays show that the switching field of the h ard layer increases significantly with decreasing element size, reaching 60 0 Oe for the smallest elements. Additionally, in patterned elements the sof t layer switches prior to field reversal due to magnetostatic coupling betw een the layers, leading to antiparallel alignment at remanence.