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Title: Voltage-controlled low-energy switching of nanomagnets through Ruderman-Kittel-Kasuya-Yosida interactions for magnetoelectric device applications

Abstract

In this article, we consider through simulation low-energy switching of nanomagnets via electrostatically gated inter-magnet Ruderman-Kittel-Kasuya-Yosida (RKKY) interactions on the surface of three-dimensional topological insulators, for possible memory and nonvolatile logic applications. We model the possibility and dynamics of RKKY-based switching of one nanomagnet by coupling to one or more nanomagnets of set orientation. Potential applications to both memory and nonvolatile logic are illustrated. Sub-attojoule switching energies, far below conventional spin transfer torque (STT)-based memories and even below CMOS logic appear possible. Switching times on the order of a few nanoseconds, comparable to times for STT switching, are estimated for ferromagnetic nanomagnets, but the approach also appears compatible with the use of antiferromagnets which may allow for faster switching.

Authors:
; ; ;  [1]
  1. Microelectronics Research Center, University of Texas at Austin, 10100 Burnet Road, Bldg. 160, Austin, Texas 78758 (United States)
Publication Date:
OSTI Identifier:
22597822
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 120; Journal Issue: 3; 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; COMPARATIVE EVALUATIONS; ELECTRIC POTENTIAL; ELECTRICAL PROPERTIES; INTERACTIONS; MAGNETIC PROPERTIES; MAGNETS; RUDERMAN-KITTEL COUPLING; SPIN; SURFACES; THREE-DIMENSIONAL CALCULATIONS; TOPOLOGY

Citation Formats

Ghosh, Bahniman, E-mail: bghosh@utexas.edu, Dey, Rik, Register, Leonard F., and Banerjee, Sanjay K. Voltage-controlled low-energy switching of nanomagnets through Ruderman-Kittel-Kasuya-Yosida interactions for magnetoelectric device applications. United States: N. p., 2016. Web. doi:10.1063/1.4959089.
Ghosh, Bahniman, E-mail: bghosh@utexas.edu, Dey, Rik, Register, Leonard F., & Banerjee, Sanjay K. Voltage-controlled low-energy switching of nanomagnets through Ruderman-Kittel-Kasuya-Yosida interactions for magnetoelectric device applications. United States. doi:10.1063/1.4959089.
Ghosh, Bahniman, E-mail: bghosh@utexas.edu, Dey, Rik, Register, Leonard F., and Banerjee, Sanjay K. 2016. "Voltage-controlled low-energy switching of nanomagnets through Ruderman-Kittel-Kasuya-Yosida interactions for magnetoelectric device applications". United States. doi:10.1063/1.4959089.
@article{osti_22597822,
title = {Voltage-controlled low-energy switching of nanomagnets through Ruderman-Kittel-Kasuya-Yosida interactions for magnetoelectric device applications},
author = {Ghosh, Bahniman, E-mail: bghosh@utexas.edu and Dey, Rik and Register, Leonard F. and Banerjee, Sanjay K.},
abstractNote = {In this article, we consider through simulation low-energy switching of nanomagnets via electrostatically gated inter-magnet Ruderman-Kittel-Kasuya-Yosida (RKKY) interactions on the surface of three-dimensional topological insulators, for possible memory and nonvolatile logic applications. We model the possibility and dynamics of RKKY-based switching of one nanomagnet by coupling to one or more nanomagnets of set orientation. Potential applications to both memory and nonvolatile logic are illustrated. Sub-attojoule switching energies, far below conventional spin transfer torque (STT)-based memories and even below CMOS logic appear possible. Switching times on the order of a few nanoseconds, comparable to times for STT switching, are estimated for ferromagnetic nanomagnets, but the approach also appears compatible with the use of antiferromagnets which may allow for faster switching.},
doi = {10.1063/1.4959089},
journal = {Journal of Applied Physics},
number = 3,
volume = 120,
place = {United States},
year = 2016,
month = 7
}
  • With the approximation that the energy gap is position independent, the static spin susceptibility in the superconducting state is completely determined by the normal-state Green functions. At low concentrations of nonmagnetic impurities, it is shown, by use of semiclassical approximations, that the usual type of Ruderman-Kittel-Kasuya-Yosida interaction acquires an additional random-phase shift. In systems where superconductivity and magnetism coexist such an effect will cause strong disorder in the magnetic phase akin to a spin-glass-like phase.
  • The magnetic transition temperatures for SmRh/sub 4/B/sub 4/ and ErRh/sub 4/B/sub 4/ are calculated for the Ruderman-Kittel-Kasuya-Yosida interaction as a function of Fermi wave-vector k/sub f/ and electron mean free path l. The results are consistent with the experimental l dependence and the antiferromagnetism (ferromagnetism) in SmRh/sub 4/B/sub 4/ (ErRh/sub 4/B/sub 4/) for values of k/sub f/ approximately equal to 1.84 A/sup -1/ (1.95 A/sup -1/). This result cannot, however, assess whether or not direct dipole-dipole interactions are significant for T/sub M/ in ErRh/sub 4/B/sub 4/.
  • Oscillations in both {ital ferromagnetic} and antiferromagnetic indirect exchange coupling through Ru are directly measured. Ferromagnetic coupling is determined by {ital spin} {ital engineering} multilayered structures comprised of trilayers of Ni{sub 80}Co{sub 20}/Ru/Ni{sub 80}Co{sub 20} in which one of the Ni{sub 80}Co{sub 20} layers is strongly antiferromagnetically pinned to a Co layer. Oscillations in antiferromagnetic exchange coupling are measured in companion Ni{sub 80}Cu{sub 20}/Ru multilayers. The dependence of the exchange coupling strength on Ru thickness is well described by the Ruderman-Kittel-Kasuya-Yosida far-field range function, providing a direct measurement of this function through a transition metal.