Two-barrier stability that allows low-power operation in current-induced domain-wall motion

Energy barriers in magnetization reversal dynamics have long been of interest because the barrier height determines the thermal stability of devices as well as the threshold force triggering their dynamics. Especially in memory and logic applications, there is a dilemma between the thermal stability of bit data and the operation power of devices, because larger energy barriers for higher thermal stability inevitably lead to larger magnetic fields (or currents) for operation. Here we show that this is not the case for current-induced magnetic domain-wall motion induced by adiabatic spin-transfer torque. By quantifying domain-wall depinning energy barriers by magnetic field and current, we find that there exist two different pinning barriers, extrinsic and intrinsic energy barriers, which govern the thermal stability and threshold current, respectively. This unique two-barrier system allows low-power operation with high thermal stability, which is impossible in conventional single-barrier systems.

[1]  C. Chappert,et al.  Domain wall creep in magnetic wires. , 2004, Physical review letters.

[2]  A. Fert,et al.  Dynamical properties of magnetization reversal in an ultrathin Au/Co film , 1995 .

[3]  Eric E. Fullerton,et al.  Reducing the critical current for spin-transfer switching of perpendicularly magnetized nanomagnets , 2009 .

[4]  K. Shin,et al.  Joule heating in ferromagnetic nanowires: Prediction and observation , 2008 .

[5]  S. Fukami,et al.  Low-current perpendicular domain wall motion cell for scalable high-speed MRAM , 2006, 2009 Symposium on VLSI Technology.

[6]  S. Yuasa,et al.  Giant room-temperature magnetoresistance in single-crystal Fe/MgO/Fe magnetic tunnel junctions , 2004, Nature materials.

[7]  F. M. Peeters,et al.  Saddle-point states and energy barriers for vortex entrance and exit in superconducting disks and rings , 2001 .

[8]  S. Fukami,et al.  Observation of the intrinsic pinning of a magnetic domain wall in a ferromagnetic nanowire. , 2011, Nature materials.

[9]  M. Gajek,et al.  Spin torque switching of 20 nm magnetic tunnel junctions with perpendicular anisotropy , 2012 .

[10]  T. Ono,et al.  Magnetization reversal in submicron magnetic wire studied by using giant magnetoresistance effect , 1998 .

[11]  S. Nasu,et al.  Real-space observation of current-driven domain wall motion in submicron magnetic wires. , 2003, Physical review letters.

[12]  Ono,et al.  Propagation of a magnetic domain wall in a submicrometer magnetic wire , 1999, Science.

[13]  Shunsuke Fukami,et al.  Temperature dependence of carrier spin polarization determined from current-induced domain wall motion in a Co/Ni nanowire , 2012 .

[14]  H. Frauenfelder,et al.  The energy landscape in non-biological and biological molecules , 1998, Nature Structural Biology.

[15]  H. Ohno,et al.  Current-induced domain-wall switching in a ferromagnetic semiconductor structure , 2004, Nature.

[16]  Sug-Bong Choe,et al.  Electric current effect on the energy barrier of magnetic domain wall depinning: origin of the quadratic contribution. , 2011, Physical review letters.

[17]  Hyun-Woo Lee,et al.  Interdimensional universality of dynamic interfaces , 2009, Nature.

[18]  H. Ohno,et al.  A perpendicular-anisotropy CoFeB-MgO magnetic tunnel junction. , 2010, Nature materials.

[19]  S. Parkin,et al.  Magnetic Domain-Wall Racetrack Memory , 2008, Science.

[20]  R. P. Robertazzi,et al.  Effect of subvolume excitation and spin-torque efficiency on magnetic switching , 2011 .

[21]  J. Katine,et al.  Time-resolved reversal of spin-transfer switching in a nanomagnet. , 2004, Physical review letters.

[22]  Y. Nakatani,et al.  Threshold Current of Domain Wall Motion under Extrinsic Pinning, β-Term and Non-Adiabaticity(Condensed matter: electronic structure and electrical, magnetic, and optical properties) , 2006 .

[23]  H. Ohno,et al.  Junction size effect on switching current and thermal stability in CoFeB/MgO perpendicular magnetic tunnel junctions , 2011 .

[24]  Hyun-Woo Lee,et al.  Current-induced domain wall motion in a nanowire width perpendicular magnetic anisotropy , 2008, 0804.3864.

[25]  M. A. Escobar,et al.  Thermal stability of patterned Co/Pd nanodot arrays , 2012 .

[26]  S. Mangin,et al.  Spin-transfer pulse switching: From the dynamic to the thermally activated regime , 2010, 1009.5240.

[27]  H. Ohno,et al.  Observation of magnetic domain-wall dynamics transition in Co/Ni multilayered nanowires , 2012 .

[28]  Lars Bocklage,et al.  Direct observation of stochastic domain-wall depinning in magnetic nanowires. , 2009, Physical review letters.

[29]  G. Tatara,et al.  Theory of current-driven domain wall motion: spin transfer versus momentum transfer. , 2004, Physical review letters.

[30]  D Petit,et al.  Magnetic Domain-Wall Logic , 2005, Science.

[31]  Teruo Ono,et al.  Temperature dependence of depinning fields in submicron magnetic wires with an artificial neck , 2005 .

[32]  I. Ryabchikov,et al.  Determination of Activation Energies of Chemical Reactions by Differential Thermal Analysis , 1966, Nature.

[33]  G. Tatara,et al.  Universality of thermally assisted magnetic domain-wall motion under spin torque , 2004, cond-mat/0411250.

[34]  C. Chappert,et al.  Non-adiabatic spin-torques in narrow magnetic domain walls , 2010 .

[35]  D. Awschalom,et al.  Measurements of nanoscale domain wall flexing in a ferromagnetic thin film. , 2011, Physical review letters.