Validity of the thermal activation model for spin-transfer torque switching in magnetic tunnel junctions

Published

April 6, 2011

Author(s)

Ranko R. Heindl, William H. Rippard, Stephen E. Russek, Matthew R. Pufall, Anthony B. Kos

Abstract

We have performed spin transfer switching experiments on nanoscale MgO magnetic tunnel junctions, with a large number of trials (up to 107 switching events) as functions of pulse voltage amplitude and duration, and compared the results with both macrospin simulations and a simple thermal model of switching. Three different methods derived from the thermally activated spin-torque-assisted switching model are used to determine the thermal stability factor and the intrinsic switching voltage from the switching distributions. Specifically, their values are determined from the read disturb rate, switching voltage vs. pulse duration, and switching voltage distribution measurements. Our conclusion is that the data obtained from the first two methods agree well with each other as well as with the values from quasistatic measurements, assuming that for the region of voltages over which the data is taken, the voltage is small compared to the intrinsic switching voltage, and the influence from other factors contributing to the switching is negligible (such as current-induced heating and field-like torque). The third method (switching voltage distribution measurements) is shown to be impractical, because the applied voltage surpasses the intrinsic switching voltage within the time-scale (

Citation

Physical Review B

Volume

109

Issue

073910

Pub Type

Journals

Download Paper

https://doi.org/10.1063/1.3562136

Keywords

MRAM, STT-RAM, spin-transfer switching, current-induced switching, thermal stability, nonvolatile memory

Citation

Heindl, R. , Rippard, W. , Russek, S. , Pufall, M. and Kos, A. (2011), Validity of the thermal activation model for spin-transfer torque switching in magnetic tunnel junctions, Physical Review B, [online], https://doi.org/10.1063/1.3562136 (Accessed December 12, 2024)