The University of Texas System

Naimul Hassan

Joseph S Friedman

Xuan Hu

Wesley H Brigner

Alvaro Velasquez

The present disclosure provides a domain wall magnetic tunnel junction device. Integration of input spikes pushes a domain wall within a ferromagnetic track toward a magnetic tunnel junction (MTJ). An energy gradient within the track pushes the domain wall away from the MTJ by leaking accumulated energy from the input spikes. If the integrated input spikes exceed the energy leak of the gradient within a specified time period, the domain wall reaches the MTJ and reverses its resistance, producing an output spike. The leaking energy gradient can be created by a magnetic field, a trapezoidal shape of the ferromagnetic track, or nonuniform material properties in the ferromagnetic track. A feedback and feedforward crossbar configuration is disclosed that provides for a neuromorphic computing system suitable for unsupervised learning.

Spintronic computing architecture and method

A magnetic tunnel junction is provided. The magnetic tunnel junction comprises an insulating tunnel barrier and a fixed ferromagnet layer adjacent the tunnel barrier. The fixed ferromagnet comprises a fixed magnetization along an easy axis approximately normal to an interface between the fixed ferromagnet and the tunnel barrier. A free ferromagnet layer is adjacent the tunnel barrier on the side opposite the fixed ferromagnet. The free ferromagnet layer comprises a bistable magnetization along the easy axis that can switch between a parallel state and an anti-parallel state with the fixed ferromagnet. A heavy metal layer is adjacent the free ferromagnet on the side opposite the tunnel barrier. A unidirectional electric current pulse through the heavy metal layer switches the bistable magnetization of the free ferromagnet, thereby switching an electrical resistance state of the magnetic tunnel junction.

Toggle spin-orbit torque MRAM with perpendicular magnetic anisotropy

The present disclosure provides a domain wall magnetic tunnel junction device. Integration of input spikes pushes a domain wall within a ferromagnetic track toward a magnetic tunnel junction (MTJ). An energy gradient within the track pushes the domain wall away from the MTJ by leaking accumulated energy from the input spikes. If the integrated input spikes exceed the energy leak of the gradient within a specified time period, the domain wall reaches the MTJ and reverses its resistance, producing an output spike. The leaking energy gradient can be created by a magnetic field, a trapezoidal shape of the ferromagnetic track, or nonuniform material properties in the ferromagnetic track.

Growing community of inventors

Dallas, TX, United States of America

Naimul Hassan