MAGNETORESISTANCE IN FE-MN NI-FE-CO/CO/CU/CO/NI-FE-CO SANDWICHES WITHNIO OR NIO/HF BUFFER LAYER/

Magnetoresistance effects and film structures have been investigated i n [Fe-Mn/Ni-Fe-Co/Co/Cu/Co/Ni-Fe-Co/NiO/Si] sandwiches. The NiO buffer layers increase exchange bias fields applied to the Ni-Fe-Co/Co magne tic bilayers neighboring with the Fe-Mn layers. However, the NiO buffe r layers decrease the magnetoresistance ratios of the sandwiches, Ther efore, we also inserted Hf buffer layers between the NiO buffer layers and the Si substrates. The Hf buffer layer, 1.0 nm in thickness, incr eases the magnetoresistance ratios of the sandwiches.