Abstract
Future generations of magnetic random access memory demand magnetic tunnel junctions that can provide simultaneously high magnetoresistance, strong retention, low switching energy, and small cell size below 10 nm. Here, we study perpendicular magnetic tunnel junctions with composite free layers, where multiple ferromagnet/nonmagnet interfaces can contribute to the thermal stability. Different nonmagnetic materials (MgO, Ta, and Mo) have been employed as the coupling layers in these multi-interface free layers. The evolution of junction properties under different annealing conditions is investigated. A strong dependence of the tunneling magnetoresistance on the thickness of the first CoFeB layer has been observed. In junctions where Mo and MgO are used as coupling layers, a large tunneling magnetoresistance above 200% has been achieved after 400 °C annealing.
| Original language | English (US) |
|---|---|
| Article number | 242404 |
| Journal | Applied Physics Letters |
| Volume | 119 |
| Issue number | 24 |
| DOIs | |
| State | Published - Dec 13 2021 |
Bibliographical note
Funding Information:This work was supported in part by Semiconductor Research Corporation through the Logic and Memory Devices program (Global Research Collaboration), by DARPA through the ERI program (FRANC), and by NSF through No. DMR-1905783. M.A. and A.L. were supported by the REU supplement of NSF via No. ECCS-1554011.
Publisher Copyright:
© 2021 Author(s).