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Title: Towards developing a compact model for magnetization switching in straintronics magnetic random access memory devices

Abstract

Strain-mediated magnetization switching in a magnetic tunneling junction (MTJ) by exploiting a combination of piezoelectricity and magnetostriction has been proposed as an energy efficient alternative to spin transfer torque (STT) and field induced magnetization switching methods in MTJ-based magnetic random access memories (MRAM). Theoretical studies have shown the inherent advantages of strain-assisted switching, and the dynamic response of the magnetization has been modeled using the Landau-Lifshitz-Gilbert (LLG) equation. However, an attempt to use LLG for simulating dynamics of individual elements in large-scale simulations of multi-megabyte straintronics MRAM leads to extremely time-consuming calculations. Hence, a compact analytical solution, predicting the flipping delay of the magnetization vector in the nanomagnet under stress, combined with a liberal approximation of the LLG dynamics in the straintronics MTJ, can lead to a simplified model of the device suited for fast large-scale simulations of multi-megabyte straintronics MRAMs. In this work, a tensor-based approach is developed to study the dynamic behavior of the stressed nanomagnet. First, using the developed method, the effect of stress on the switching behavior of the magnetization is investigated to realize the margins between the underdamped and overdamped regimes. The latter helps the designer realize the oscillatory behavior of the magnetization when settlingmore » along the minor axis, and the dependency of oscillations on the stress level and the damping factor. Next, a theoretical model to predict the flipping delay of the magnetization vector is developed and tested against LLG-based numerical simulations to confirm the accuracy of findings. Lastly, the obtained delay is incorporated into the approximate solutions of the LLG dynamics, in order to create a compact model to liberally and quickly simulate the magnetization dynamics of the MTJ under stress. Using the developed delay equation, the efficiency of the straintronics switching over the STT method is highlighted by analytically investigating the energy-delay trade-off of both methodologies.« less

Authors:
; ;  [1]
  1. Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, Michigan 48109-2121 (United States)
Publication Date:
OSTI Identifier:
22598900
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 120; Journal Issue: 7; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ANALYTICAL SOLUTION; APPROXIMATIONS; COMPUTERIZED SIMULATION; MAGNETIZATION; MAGNETOSTRICTION; MEMORY DEVICES; PIEZOELECTRICITY; RANDOMNESS; SPIN; STRAINS; STRESSES; TORQUE; TUNNEL EFFECT; VECTORS

Citation Formats

Barangi, Mahmood, E-mail: barangi@umich.edu, Erementchouk, Mikhail, and Mazumder, Pinaki. Towards developing a compact model for magnetization switching in straintronics magnetic random access memory devices. United States: N. p., 2016. Web. doi:10.1063/1.4960952.
Barangi, Mahmood, E-mail: barangi@umich.edu, Erementchouk, Mikhail, & Mazumder, Pinaki. Towards developing a compact model for magnetization switching in straintronics magnetic random access memory devices. United States. doi:10.1063/1.4960952.
Barangi, Mahmood, E-mail: barangi@umich.edu, Erementchouk, Mikhail, and Mazumder, Pinaki. 2016. "Towards developing a compact model for magnetization switching in straintronics magnetic random access memory devices". United States. doi:10.1063/1.4960952.
@article{osti_22598900,
title = {Towards developing a compact model for magnetization switching in straintronics magnetic random access memory devices},
author = {Barangi, Mahmood, E-mail: barangi@umich.edu and Erementchouk, Mikhail and Mazumder, Pinaki},
abstractNote = {Strain-mediated magnetization switching in a magnetic tunneling junction (MTJ) by exploiting a combination of piezoelectricity and magnetostriction has been proposed as an energy efficient alternative to spin transfer torque (STT) and field induced magnetization switching methods in MTJ-based magnetic random access memories (MRAM). Theoretical studies have shown the inherent advantages of strain-assisted switching, and the dynamic response of the magnetization has been modeled using the Landau-Lifshitz-Gilbert (LLG) equation. However, an attempt to use LLG for simulating dynamics of individual elements in large-scale simulations of multi-megabyte straintronics MRAM leads to extremely time-consuming calculations. Hence, a compact analytical solution, predicting the flipping delay of the magnetization vector in the nanomagnet under stress, combined with a liberal approximation of the LLG dynamics in the straintronics MTJ, can lead to a simplified model of the device suited for fast large-scale simulations of multi-megabyte straintronics MRAMs. In this work, a tensor-based approach is developed to study the dynamic behavior of the stressed nanomagnet. First, using the developed method, the effect of stress on the switching behavior of the magnetization is investigated to realize the margins between the underdamped and overdamped regimes. The latter helps the designer realize the oscillatory behavior of the magnetization when settling along the minor axis, and the dependency of oscillations on the stress level and the damping factor. Next, a theoretical model to predict the flipping delay of the magnetization vector is developed and tested against LLG-based numerical simulations to confirm the accuracy of findings. Lastly, the obtained delay is incorporated into the approximate solutions of the LLG dynamics, in order to create a compact model to liberally and quickly simulate the magnetization dynamics of the MTJ under stress. Using the developed delay equation, the efficiency of the straintronics switching over the STT method is highlighted by analytically investigating the energy-delay trade-off of both methodologies.},
doi = {10.1063/1.4960952},
journal = {Journal of Applied Physics},
number = 7,
volume = 120,
place = {United States},
year = 2016,
month = 8
}
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