Current-induced magnetization switching in MgO barrier magnetic tunnel junctions with CoFeB based synthetic ferrimagnetic free layers
arXiv:0801.1355 · doi:10.1109/TMAG.2008.924545
Abstract
We investigated the effect of using a synthetic ferrimagnetic (SyF) free layer in MgO-based magnetic tunnel junctions (MTJs) on current-induced magnetization switching (CIMS), particularly for application to spin-transfer torque random access memory (SPRAM). The employed SyF free layer had a Co40Fe40B20/ Ru/ Co40Fe40B20 and Co20Fe60B20/Ru/Co20Fe60B20 structures, and the MTJs(100x(150-300) nm^2) were annealed at 300oC. The use of SyF free layer resulted in low intrinsic critical current density (Jc0) without degrading the thermal-stability factor (E/kBT, where E, kB, and T are the energy potential, the Boltzmann constant, and temperature,respectively). When the two CoFeB layers of a strongly antiferromagnetically coupled SyF free layer had the same thickness, Jc0 was reduced to 2-4x10^6 A/cm^2. This low Jc0 may be due to the decreased effective volume under the large spin accumulation at the CoFeB/Ru. The E/kBT was over 60, resulting in a retention time of over ten years and suppression of the write current dispersion for SPRAM. The use of the SyF free layer also resulted in a bistable (parallel/antiparallel) magnetization configuration at zero field, enabling the realization of CIMS without the need to apply external fields to compensate for the offset field.
6 pages
References in corpus (13)
- Currents, Torques, and Polarization Factors in Magnetic Tunnel Junctions
- Thermally assisted magnetization reversal in the presence of a spin-transfer torque
- Dependence of Giant Tunnel Magnetoresistance of Sputtered CoFeB/MgO/CoFeB Magnetic Tunnel Junctions on MgO Barrier Thickness and Annealing Temperatur
- Spin Transfer Switching and Spin Polarization in Magnetic Tunnel Junctions with Mgo and Alox Barriers
- Effect of high annealing temperature on giant tunnel magnetoresistance ratio of CoFeB/MgO/CoFeB magnetic tunnel junctions
- Current-driven magnetization switching in CoFeB/MgO/CoFeB magnetic tunnel junctions
- Giant tunnel magnetoresistance and high annealing stability in CoFeB/MgO/CoFeB magnetic tunnel junctions with synthetic pinned layer
- Current-induced magnetization switching in MgO barrier based magnetic tunnel junctions with CoFeB/Ru/CoFeB synthetic ferrimagnetic free layer
- Dependence of tunnel magnetoresistance in MgO based magnetic tunnel junctions on Ar pressure during MgO sputtering
- Magnetization reversal by injection and transfer of spin: experiments and theory
- Thermal Effects on the Magnetic Field Dependence of Spin Transfer Induced Magnetization Reversal
- Antiferromagnetically coupled CoFeB/Ru/CoFeB trilayers
- Dependence of tunnel magnetoresistance on ferromagnetic electrode materials in MgO-barrier magnetic tunnel junctions
Cited by in corpus (10)
- Shape anisotropy revisited in single-digit nanometer magnetic tunnel junctions
- Thermally assisted spin transfer torque switching in synthetic free layers
- Self-consistent calculation of spin transport and magnetization dynamics
- Thermal switching rate of a ferromagnetic material with uniaxial anisotropy
- Ultrafast Spin-Transfer-Torque Switching of Synthetic Ferrimagnets
- Critical current density for spin transfer torque switching with composite free layer structure
- Minimization of the Switching Time of a Synthetic Free Layer in Thermally Assisted Spin Torque Switching
- Temperature-dependent Magnetic Transitions in CoCrPt-Ru-CoCrPt Synthetic Ferrimagnets
- Spin-torque nano-oscillator based on two in-plane magnetized synthetic ferrimagnets
- Theory of Spin Torque Assisted Thermal Switching of Single Free Layer