This study reports the current-induced switching of a Co20Fe60B20/MgO/Co20Fe60B20-based perpendicular magnetic tunnel junction (p-MTJ) with a [Co/Pt]4 stack as a synthetic anti-ferromagnetic (SAF) layer. Electrical and spectroscopic evidence of p-MTJs reveals that the pinning of the Co20Fe60B20 layer by the SAF through a Ta spacer layer enhances the switching resistance after annealing at 650 K (375 °C). A drastic improvement of 6 times in the tunneling magnetoresistance (TMR) was observed after annealing in an external magnetic field (14% for as-deposited and 83% for annealed both for zero bias). The TMR also shows a gradual increased behavior with bias at room temperature, which may be attributed to the multi-domain switching with increase in current. The analogous SAF-based MTJ devices were modeled using the non-equilibrium Green's function (NEGF) to validate the experimental results. The existence of a stable TMR and the low switching current density of the fabricated p-MTJ structures provides higher reliability and low-power operation. This makes it attractive for next-generation MTJ applications, especially for embedded memory, system-on-chip, IoT, and neuromorphic computing applications.
Bibliographical noteFunding Information:
This work was supported under the financial support of IIT Mandi seed grant IITM/SG/SS/62. The authors thank the C4DFED and AMRC centers at IIT Mandi for providing device fabrication, characterization, and materials characterization facilities; the Nanoscience Centre, IIT Kanpur for assistance in X-ray diffraction analysis; Mr. Ratul Paul from Thermo-Fisher for depth profile analysis; and Dr. Mahesh Soni and Ms. Shivangi Shringi from SCEE, IIT Mandi for valuable discussions. MGM is supported under the “Visvesvaraya PhD Scheme” by MEiTY, India.
Copyright © 2019 American Chemical Society.
- increasing tunneling magnetoresistance
- low switching current density
- non-equilibrium Green's function
- perpendicular magnetic tunnel junction
- synthetic anti-ferromagnetic
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Materials Chemistry