Abstract
A highly efficient exchange-coupled free-layer spin-orbit torque (SOT) magnetic random access memory cell is proposed for ultra-high-density memory. By exploiting typically unrealized benefits of SOT - in particular, its compatibility with low-damping magnetic insulators and the energy efficiencies associated with exchange coupling of hard/soft composite structures - a write energy of 18 aJ/bit for 1 ns switching is achieved. Furthermore, high magnetocrystalline anisotropy materials such as L10-FePt or L10-FePd are employed not only to facilitate achievement of ultra-high-density memory but also to allow for reduction of heavy metal layer volume and a reduction in write energy not seen in previous CoFeB-based cells. This energy is within a factor 72 of the theoretical limit of 60k BT. It also represents a factor of >500 improvement relative to state-of-the-art DDR4 DRAM cells.
| Original language | English (US) |
|---|---|
| Article number | 8403885 |
| Journal | IEEE Transactions on Magnetics |
| Volume | 54 |
| Issue number | 11 |
| DOIs | |
| State | Published - Nov 2018 |
Bibliographical note
Funding Information:The authors would like to thank A. Venugopal and T. Qu for useful discussion. This work was supported in part by C-SPIN, one of six centers of STARnet, a Semiconductor Research Corporation program, sponsored by MARCO and DARPA.
Publisher Copyright:
© 1965-2012 IEEE.
Keywords
- Composite free layer
- magnetic insulator (MI)
- micromagnetic simulation
- spin-orbit torque (SOT)
