This article has been accepted for inclusion in a future issue of this journal. Content is final as presented, with the exception of pagination. IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS—I: REGULAR PAPERS 1 A Survey on Circuit Modeling of Spin-Transfer- T

Abstract—Accurate modeling of magnetic tunnel junction (MTJ) is critical for design of memories such as spin-transfer-torque magnetoresistive random access memory (STT-MRAM) and spin logic circuits such as spin flip flops. This paper reviews several static and dynamic models for the MTJ and compares them for their capabilities and limitations. Furthermore, a Ver-ilog-A model is developed to predict dynamic characteristics of the MTJ. These models are used in simulating a prototype circuit to illustrate their strengths and weaknesses. Index Terms—Magnetic tunnel junction (MTJ), magne-toresistive random-access memory (MRAM), modeling, spin-transfer-torque (STT). I