Spin dependent tunnel junctions for memory and read-head applications

Spin dependent tunnel junctions with TMR exceeding 30-40% can now be prepared with AlOx and AlN barriers, with junction resistance tuned from 30-40 Omega x mum(2) to 10(8) Omega x mum(2). Thermal stability is better than 300 degreesC for thicker barriers (>11 Angstrom) but is degraded to 220 degreesC for 6 Angstrom barriers. A 9 bit MRAM cell is demonstrated using tunnel junctions and vertically integrated a:Si diodes, Junction switching is achieved with on chip 20 ns field pulses. Requirements for tunnel junctions for 100 Gbit/in(2) read head applications are discussed. First prototypes of tunnel junction read heads with 600 Angstrom read gaps were fabricated, where the TJ is at the air bearing surface. TMR loss was observed during the final head lapping steps.