Comprehensive and Macrospin-Based Magnetic Tunnel Junction Spin Torque Oscillator Model-Part I: Analytical Model of the MTJ STO

Magnetic tunnel junction (MTJ) spin torque oscillators (STOs) have shown the potential to be used in a wide range of microwave and sensing applications. To evaluate the potential uses of MTJ STO technology in various applications, an analytical model that can capture MTJ STO's characteristics, while enabling system- and circuit-level designs, is of great importance. An analytical model based on macrospin approximation is necessary for these designs since it allows implementation in hardware description languages. This paper presents a new macrospin-based, comprehensive, and compact MTJ STO model, which can be used for various MTJ STOs to estimate the performance of MTJ STOs together with their application-specific integrated circuits. To adequately present the complete model, this paper is divided into two parts. In Part I, the analytical model is introduced and verified by comparing it against measured data of three different MTJ STOs, varying the angle and magnitude of the magnetic field, as well as the DC biasing current. The proposed analytical model is suitable for being implemented in Verilog-A and used for efficient simulations at device, circuit, and system levels. In Part II, the full Verilog-A implementation of the analytical model with accurate phase noise generation is presented and verified by simulations.

[1]  Berger.  Emission of spin waves by a magnetic multilayer traversed by a current. , 1996, Physical review. B, Condensed matter.

[2]  W. Park,et al.  Perpendicular giant magnetoresistance of Co91Fe9/Cu exchange-biased spin-valves: further evidence for a unified picture , 1999 .

[3]  John Casimir Slonczewski,et al.  Excitation of spin waves by an electric current , 1999 .

[4]  H. Oshima,et al.  Perpendicular giant magnetoresistance of CoFeB/Cu single and dual spin-valve films , 2002 .

[5]  J. C. Sloncxewski.  Current-driven excitation of magnetic multilayers , 2003 .

[6]  D. Ralph,et al.  Microwave oscillations of a nanomagnet driven by a spin-polarized current , 2003, Nature.

[7]  S. E. Russek,et al.  Frequency modulation of spin-transfer oscillators , 2005 .

[8]  D. Ralph,et al.  Time-Domain Measurements of Nanomagnet Dynamics Driven by Spin-Transfer Torques , 2005, Science.

[9]  S. Yuasa,et al.  Spin-torque diode effect in magnetic tunnel junctions , 2005, Nature.

[10]  Mark D. Stiles,et al.  Spin-Transfer Torque and Dynamics , 2006 .

[11]  D. Ralph,et al.  Measurement of the spin-transfer-torque vector in magnetic tunnel junctions , 2007, 0705.4207.

[12]  Bernard Dieny,et al.  Modeling of the perpendicular polarizer-planar free layer spin torque oscillator: Micromagnetic simulations , 2008 .

[13]  S. Yuasa,et al.  Quantitative measurement of voltage dependence of spin-transfer torque in MgO-based magnetic tunnel junctions , 2008 .

[14]  Hitoshi Kubota,et al.  Bias-driven high-power microwave emission from MgO-based tunnel magnetoresistance devices , 2008, 0803.2013.

[15]  V. Tiberkevich,et al.  Nonlinear Auto-Oscillator Theory of Microwave Generation by Spin-Polarized Current , 2009, IEEE Transactions on Magnetics.

[16]  J. Katine,et al.  Experimental test of an analytical theory of spin-torque-oscillator dynamics , 2008, 0812.0541.

[17]  Johan Åkerman,et al.  Spin torque oscillator frequency versus magnetic field angle: The prospect of operation beyond 65 GHz , 2009 .

[18]  B. Gurney,et al.  Nanoscale magnetic field detection using a spin torque oscillator , 2010, Nanotechnology.

[19]  W. Rippard,et al.  Nonwhite frequency noise in spin torque oscillators and its effect on spectral linewidth , 2010, 1005.5372.

[20]  Ye. Pogoryelov,et al.  Nonlinear frequency and amplitude modulation of a nanocontact-based spin-torque oscillator , 2009, 0910.2819.

[21]  D. Mauri,et al.  Amplitude and phase noise of magnetic tunnel junction oscillators , 2010 .

[22]  Johan AAkerman,et al.  Bias dependence of perpendicular spin torque and of free- and fixed-layer eigenmodes in MgO-based nanopillars , 2011, 1101.2401.

[23]  Kang L. Wang,et al.  Enhancement of microwave emission in magnetic tunnel junction oscillators through in-plane field orientation , 2011 .

[24]  Olle Heinonen,et al.  Intrinsic frequency doubling in a magnetic tunnel junction–based spin torque oscillator , 2011 .

[25]  Xuanyao Fong,et al.  Spin-Transfer Torque MRAMs for Low Power Memories: Perspective and Prospective , 2012, IEEE Sensors Journal.

[26]  F. Ebrahimi,et al.  Magnetic Tunnel Junction-Based Spintronic Logic Units Operated by Spin Transfer Torque , 2012, IEEE Transactions on Nanotechnology.

[27]  Weisheng Zhao,et al.  Compact Modeling of Perpendicular-Anisotropy CoFeB/MgO Magnetic Tunnel Junctions , 2012, IEEE Transactions on Electron Devices.

[28]  Hyungsoon Shin,et al.  Advanced Circuit-Level Model of Magnetic Tunnel Junction-based Spin-Torque Oscillator with Perpendicular Anisotropy Field , 2013 .

[29]  Hyungsoon Shin,et al.  A New Circuit Model for Spin-Torque Oscillator Including Perpendicular Torque of Magnetic Tunnel Junction , 2013 .

[30]  K. Roy,et al.  Physics-Based SPICE-Compatible Compact Model for Simulating Hybrid MTJ/CMOS Circuits , 2013, IEEE Transactions on Electron Devices.

[31]  P. Gangmei,et al.  Thermal and spin-transfer-torque excitation of precessional modes in magnetic tunnel junction nanopillars with symmetric interfaces and a thick free layer , 2013 .

[32]  Saul Rodriguez,et al.  A highly tunable microwave oscillator based on MTJ STO technology , 2014 .

[33]  V. Cros,et al.  Spin-torque building blocks. , 2014, Nature Materials.

[34]  Olle Heinonen,et al.  Generation linewidth of mode-hopping spin torque oscillators , 2013, 1311.7660.

[35]  Saul Rodriguez,et al.  Comprehensive and Macrospin-Based Magnetic Tunnel Junction Spin Torque Oscillator Model- Part II: Verilog-A Model Implementation , 2014, IEEE Transactions on Electron Devices.