A Voltage-Controlled Gain Cell Magnetic Memory

Abstract

This letter presents a magnetic gain cell structure that consists of a new kind of voltage-controlled magnetic tunnel junction (MTJ) and two transistors for a large separation in the output current for the two memory states while retaining the low power advantages of a voltage-controlled write mechanism. The voltage-controlled MTJ utilizes the interlayer exchange coupling and the resonant tunneling phenomena to enable a resonant-exchange-controlled (REC) magnetization switching, leading to a substantially low write energy and delay, in the order of 29.5 fJ/bit and 1.6 ns, respectively. Two transistors in a gain cell configuration can provide a 103 times change in the output current between the 0 and 1 states from a ~25% magnetoresistance of the REC MTJ with a high baseline resistance in the order of a few $\text{M}\Omega $ . Such a magnetic gain-cell also exhibits low read energy and delay, in the range of 7.6~39 fJ/bit and 0.6~1 ns, thus promising for low energy, fast, and high-density memory technologies.