The Magnetic Tunnel Junction (MTJ) is a spintronic device that is gaining attention in hybrid- and post-silicon memory and logic circuit designs. The device consists of two thin film ferromagnets separated by a nanometer thin oxide layer. The resistance of this device depends on the relative angle between the magnetizations of the two ferromagnets, and can be used to create a memory device by storing information as the relative configuration (anti-parallel and parallel) of the angle. Using the phenomena of spin transfer torque, this angle can be controlled and used to write information as well, making MTJ capable of working as a solid state non-volatile memory. Other features like low power operation, radiation hardening, high projected relatibility and size scalability make MTJs a candidate for "universal memory".
We present a Non-Equilibrium Green’s Function (NEGF) based quantum transport simulator that calculates critical transport properties of an MTJ viz. Parallel and Anti-Parallel Resistances, Tunneling Magneto-Resistance (TMR) and Spin Transfer Torque (STT, both in-plane and out of the plane), using material parameters and geometric dimensions of an MTJ device as inputs. The underlying model is the first model to quantitatively benchmark multiple experimental data and was published in a peer reviewed journal.
D. Datta, B. Behin-Aein, S. Datta, and S. Salahuddin, “Voltage Asymmetry of Spin-Transfer Torques,” IEEE Transactions on Nanotechnology, vol. 11, no. 2, pp. 261–272, 2012.
Researchers should cite this work as follows:
Samiran Ganguly, Deepanjan Datta, Chen Shang, Sankarsh Ramadas, Sayeef Salahuddin, Supriyo Datta (2014), "Magnetic Tunnel Junction Lab," http://nanohub.org/resources/mtjlab. (DOI: 10.4231/D30Z70X0J).