Study of magnetic tunnel junction read sensors

Unshielded magnetic tunnel junction (MTJ) sensors stabilized by insulating hard magnetic tails have been fabricated. Testing results showed that the control of oxidation condition was important for obtaining MTJ with low junction resistances and high TMR coefficients. The results also showed that the thickness of insulating spacer between hard magnet and MTJ stack had a significant influence on sensor stability. Finally, recording tests of stabilized MTJ read heads demonstrated linear densities of 420 Kbpi at 10-9 ontrack error.