Macro-spin Modeling and Experimental Study of Spin-orbit Torque Biased Magnetic Sensors

Abstract

We reported a systematic study of spin-orbit torque biased magnetic sensors based on NiFe/Pt bilayers through both macro-spin modeling and experiments. The simulation results show that it is possible to achieve a linear sensor with a dynamic range of 0.1 - 10 Oe, power consumption of 1uW - 1 mW, and sensitivity of 0.1-0.5 Ohm/Oe. These characteristics can be controlled by varying the sensor dimension and current density in the Pt layer. The latter is in the range of 1 x 10^5 - 10^7 A/cm^2. Experimental results of fabricated sensors with selected sizes agree well with the simulation results. For a Wheatstone bridge sensor comprising of four sensing elements, a sensitivity up to 0.548 Ohm/Oe, linearity error below 6%, and detectivity of about 2.8 nT/Sqrt(Hz) were obtained. The simple structure and ultrathin thickness greatly facilitate the integration of these sensors for on-chip applications. As a proof-of-concept experiment, we demonstrate its application in detection of current flowing in an on-chip Cu wire.

30 pages, 12 figures

References in corpus (6)

• Theory of spin Hall magnetoresistance
• On the origin of field-like spin-orbit torques in heavy metal-ferromagnet-oxide thin film heterostructures
• Microscopic Theory of Rashba Interaction in Magnetic Metal
• Angular dependence of spin-orbit spin transfer torques
• Field-like spin orbit torque in ultra-thin polycrystalline FeMn films
• Semitransparent anisotropic and spin Hall magnetoresistance sensor enabled by spin-orbit toque biasing

Cited by in corpus (3)

• Eddy Current Testing of Metal Cracks Using Spin Hall Magnetoresistance Sensor and Machine Learning
• Spin Hall magnetoresistance sensor using Au${}_x$Pt${}_{1-x}$ as the spin-orbit torque biasing layer
• Spin-Orbit Torque in a Single Ferromagnetic Layer with Large Spin-Orbit Coupling