Sub-10 nm magnetic sensor for gigahertz operation using lateral spin valve structure

Abstract

We present a new magnetic sensor design using a lateral spin valve (LSV) structure that features a sensing end less than 10 nm thick, making it suitable for integration with nanoscale devices. Shot noise reduction and signal-to-noise ratio (SNR) improvement under gigahertz operation are expected for our design. The spin detection part of the LSV forms a magnetic tunnel junction (MTJ) beneath the aluminum channel. We propose to replace the single layer ferromagnet in the spin detection part of the LSV with a synthetic antiferromagnetic structure: this facilitates spin-transfer torque (STT) induced magnetization switching. Macrospin simulation shows that interlayer magnetic dipole coupling helps STT switching while interlayer exchange coupling hurts, owing to their different precession symmetries in the out-of-plane direction. It also shows that SNR > 20 dB can be achieved for a pseudorandom binary sequence with a minimum bit length 0.5 ns.