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Joule heating in nanowires

Joule heating in nanowires
Joule heating in nanowires
We study the effect of Joule heating from electric currents flowing through ferromagnetic nanowires on the temperature of the nanowires and on the temperature of the substrate on which the nanowires are grown. The spatial current density distribution, the associated heat generation, and diffusion of heat is simulated within the nanowire and the substrate. We study several different nanowire and constriction geometries as well as different substrates: (thin) silicon nitride membranes, (thick) silicon wafers, and (thick) diamond wafers. The spatially resolved increase in temperature as a function of time is computed. For effectively three-dimensional substrates (where the substrate thickness greatly exceeds the nanowire length), we identify three different regimes of heat propagation through the substrate: regime (i), where the nanowire temperature increases approximately logarithmically as a function of time. In this regime, the nanowire temperature is well-described analytically by You et al. [APL89, 222513 (2006)]. We provide an analytical expression for the time tc that marks the upper applicability limit of the You model. After tc, the heat flow enters regime (ii), where the nanowire temperature stays constant while a hemispherical heat front carries the heat away from the wire and into the substrate. As the heat front reaches the boundary of the substrate, regime (iii) is entered where the nanowire and substrate temperature start to increase rapidly. For effectively two-dimensional substrates (where the nanowire length greatly exceeds the sub- strate thickness), there is only one regime in which the temperature increases logarithmically with time for large times. We provide an analytical expression, valid for all pulse durations, that allows one to accurately compute this temperature increase in the nanowire on thin substrates
1550-235X
054437-[12pp]
Fangohr, H.
9b7cfab9-d5dc-45dc-947c-2eba5c81a160
Chernyshenko, D.
8ff59c7e-7d2c-4188-94e9-fe9a13733903
Franchin, Matteo
9e00aaa2-959e-420f-854c-3b43aece85e3
Fischbacher, Thomas
d3282f31-0a6a-4d19-80d0-e3bebc12f67a
Meier, G.
c424c194-b04c-4719-9514-d4c26bf902fa
Fangohr, H.
9b7cfab9-d5dc-45dc-947c-2eba5c81a160
Chernyshenko, D.
8ff59c7e-7d2c-4188-94e9-fe9a13733903
Franchin, Matteo
9e00aaa2-959e-420f-854c-3b43aece85e3
Fischbacher, Thomas
d3282f31-0a6a-4d19-80d0-e3bebc12f67a
Meier, G.
c424c194-b04c-4719-9514-d4c26bf902fa

Fangohr, H., Chernyshenko, D., Franchin, Matteo, Fischbacher, Thomas and Meier, G. (2011) Joule heating in nanowires. Physical Review B, 84 (5), 054437-[12pp]. (doi:10.1103/PhysRevB.84.054437).

Record type: Article

Abstract

We study the effect of Joule heating from electric currents flowing through ferromagnetic nanowires on the temperature of the nanowires and on the temperature of the substrate on which the nanowires are grown. The spatial current density distribution, the associated heat generation, and diffusion of heat is simulated within the nanowire and the substrate. We study several different nanowire and constriction geometries as well as different substrates: (thin) silicon nitride membranes, (thick) silicon wafers, and (thick) diamond wafers. The spatially resolved increase in temperature as a function of time is computed. For effectively three-dimensional substrates (where the substrate thickness greatly exceeds the nanowire length), we identify three different regimes of heat propagation through the substrate: regime (i), where the nanowire temperature increases approximately logarithmically as a function of time. In this regime, the nanowire temperature is well-described analytically by You et al. [APL89, 222513 (2006)]. We provide an analytical expression for the time tc that marks the upper applicability limit of the You model. After tc, the heat flow enters regime (ii), where the nanowire temperature stays constant while a hemispherical heat front carries the heat away from the wire and into the substrate. As the heat front reaches the boundary of the substrate, regime (iii) is entered where the nanowire and substrate temperature start to increase rapidly. For effectively two-dimensional substrates (where the nanowire length greatly exceeds the sub- strate thickness), there is only one regime in which the temperature increases logarithmically with time for large times. We provide an analytical expression, valid for all pulse durations, that allows one to accurately compute this temperature increase in the nanowire on thin substrates

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Fangohr_etal_JouleHeatingInNanoWires_PRB_84_054437_2011.pdf - Accepted Manuscript
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More information

Published date: 11 August 2011
Organisations: Computational Engineering and Design

Identifiers

Local EPrints ID: 184837
URI: https://eprints.soton.ac.uk/id/eprint/184837
ISSN: 1550-235X
PURE UUID: c120bba3-60bc-4cca-9dcf-8f22db63c04d

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Date deposited: 09 May 2011 12:26
Last modified: 18 Jul 2017 11:50

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Contributors

Author: H. Fangohr
Author: D. Chernyshenko
Author: Matteo Franchin
Author: Thomas Fischbacher
Author: G. Meier

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