Low-resistance tunnel magnetoresistive head

A tunnel magnetoresistive (TMR) head with a low resistance of about 30 Omeg a and effective track width of 1.4 mum was fabricated using an in situ natu ral oxidation (ISNO) technique. Its read-output was almost the same as that expected from test elements at the wafer level. We found no large differen ce in noise voltages between TMR head and GMR head when their resistance wa s about 30 Omega. A very low-resistivity TMR element with a resistance-area product of 14 Omega . mum(2) and a fairly high DeltaR/R of 14% was also de veloped using ISNO, A signal-to-noise ratio consideration suggests that suc h low resistance is a key to TMR heads for high recording densities.