Evaluation of Front Flux Guide-Type Magnetic Tunnel Junction Heads

Magnetic tunnel junction (MTJ) heads have been successfully fabricated using the free layer as flux guide to prevent electrical short during the definition of the air bearing surface (ABS). For a 6 Gbits/[in.sup.2] design, an output as high as 5740 [micro]Vpp was achieved for 3 mA sense current, and the output waveform was stable and noise free. Noise analysis confirmed that shot noise is prevailing in these MTJ heads, suggesting that the junction resistance has to be further reduced to challenge spin-valve heads in term of signal to noise ratio. Landau-Lifshitz-Gilbert simulations showed that for 20 Gbits/[in.sup.2] application, the flux guide height should not exceed 0. [micro]m. Index Terms--Magnetic recording/magnetic tunnel junction heads, front flux guide, shot noise, micromagnetic simulation.