Enhanced stability against spin torque noise in current perpendicular to the plane self-biased differential dual spin valves

We present a detailed study of spin-transfer torque induced noise in self-biased differential dual spin valves (DDSV) which could be potentially used as magnetic read-heads for hard-disk drives. Micromagnetics studies of DDSV were performed in all the major magnetic configurations experienced by read-heads and we show that in every case, self-biased DDSV provide a much stronger stability against spin-transfer torque noise than conventional spin valves. Provided are also insights on the influence of the dipolar interlayer coupling, shape anisotropy, exchange bias and relative orientation between the 2 free layers. Our results demonstrate the viability of DDSV read-heads for future hard disk drives generations. - Highlights: • DDSVs show better stability against STT noise as compared to single spin valves. • Flux-closure configuration plays a key role in stabilizing the DDSV against STT noise. • Anti-ferromagnetic interlayer coupling shifts the critical current density for onset of noise. • Gap layer thickness has to be controlled carefully to avoid ferromagnetic coupling