W. H. Butler

Advances and Future Prospects of Spin-Transfer Torque Random Access Memory

Spin-transfer torque random access memory (STT-RAM) is a potentially revolutionary universal memory technology that combines the capacity and cost benefits of DRAM, the fast read and write performance of SRAM, the non-volatility of Flash, and essentially unlimited endurance. In order to realize a small cell size, high speed and achieve a fully functional STT-RAM chip, the MgO-barrier magnetic tunnel junctions (MTJ) used as the core storage and readout element must meet a set of performance requirements on switching current density, voltage, magneto-resistance ratio (MR), resistance-area product (RA), thermal stability factor (¿) , switching current distribution, read resistance distribution and reliability. In this paper, we report the progress of our work on device design, material improvement, wafer processing, integration with CMOS, and testing for a demonstration STT-RAM test chip, and projections based on modeling of the future characteristics of STT-RAM.

Large magnetoresistance in bcc Co ∕ Mg O ∕ Co and Fe Co ∕ Mg O ∕ Fe Co tunnel junctions

By use of first-principles electronic structure calculations, we predict that the magnetoresistance of the bcc

Basic principles of STT-MRAM cell operation in memory arrays

\mathrm{Co}(100)∕\mathrm{Mg}\mathrm{O}(100)∕\mathrm{bcc}\mathrm{Co}(100)

Anomalous bias dependence of spin torque in magnetic tunnel junctions.

and

Electronic structure, exchange interactions, and Curie temperature of FeCo

\mathrm{Fe}\mathrm{Co}(100)∕\mathrm{Mg}\mathrm{O}(100)∕\mathrm{Fe}\mathrm{Co}(100)

COUPLING MECHANISMS IN EXCHANGE BIASED FILMS (INVITED)

tunneling junctions can be several times larger than the very large magnetoresistance predicted for the

Temperature and particle-size dependence of the equilibrium order parameter of FePt alloys

\mathrm{Fe}(100)∕\mathrm{Mg}\mathrm{O}(100)∕\mathrm{Fe}(100)

Mono-, few-, and multiple layers of copper antimony sulfide (CuSbS2): a ternary layered sulfide.

system. The origin of this large magnetoresistance can be understood by considering the electrons at the Fermi energy traveling perpendicular to the interfaces. For the minority spins there is no state with

Switching Distributions for Perpendicular Spin-Torque Devices Within the Macrospin Approximation

{\ensuremath{\Delta}}_{1}

Tunneling magnetoresistance from a symmetry filtering effect

symmetry whereas for the majority spins there is only a