Magnetic tunnel junctions deposited on highly (001) textured seed layer for low RA sensor application

Abstract This study demonstrates that RuAl seed layers with the B2 structure effectively promote (001) texture in CoFe/MgO/CoFe films, enabling epitaxial growth by magnetron sputtering and smooth interfaces even on amorphous seed layers. Tunneling magnetoresistance (TMR) devices having RuAl/NiAl/CoFe/MgO/CoFe stacks achieved over 100% TMR ratio at RA values below 0.2 Ω · μ m 2 , confirming the effectiveness of RuAl as a textured seed layer. Additionally RuAl spacers in synthetic antiferromagnetic (AF) structures exhibited strong AF coupling, offering potential for magnetic sensor integration. While Fe–Si–Al and Co–Mn–Al showed improved magnetic softness and reduced magnetostriction, their compatibility with MgO barriers requires further investigation due to concerns about diffusion and oxidation.