Multilevel Resistance Switching and Enhanced Spin Transition Temperature in Single- and Double-Molecule Spin Crossover Nanogap Devices
Gee, Alex; Jaafar, Ayoub H; Brachňaková, Barbora; Massey, Jamie; Marrows, Christopher H; Šalitroš, Ivan; Kemp, N. T.
Ayoub H Jaafar
Christopher H Marrows
Dr Neil Kemp N.Kemp@hull.ac.uk
Director of Postgraduate Researchers (Physics and Mathematics), Senior Lecturer in Physics
Dr Neil Kemp N.Kemp@hull.ac.uk
Spin crossover (SCO) molecules are promising bi-stable magnetic switches with applications in molecular spintronics. However, little is known about the switching effects of a single SCO molecule when it is confined between two metal electrodes. Here we examine the switching properties of a [Fe(III)(EtOSalPet)(NCS)] SCO molecule that is specifically tailored for surface deposition and binding to only one gold electrode in a nanogap device. Temperature dependent conductivity measurements on SCO molecule containing electromigrated gold break junctions show voltage independent telegraphic-like switching between two resistance states at temperature below 200 K. The transition temperature is very different from the transition temperature of 83 K that occurs in a bulk film of the same material. This indicates that the bulk, cooperative SCO phenomenon is no longer preserved for a single molecule and that the surface interaction drastically increases the temperature of the SCO phenomenon. Another key finding of this work is that some devices show switching between multiple resistance levels. We propose that in this case, two SCO molecules are present within the nanogap with both participating in the electronic transport and switching. Introduction The ability of spin crossover (SCO) compounds to exist in a bi-stable spin configuration makes them an attractive candidate for constructing new spintronic devices. SCO compounds have already been employed in the design of electromechanical actuators, 1 thermochromic displays 2 and data storage. 3 However, there remains a long way to go from current research to the ultimate goal of using these compounds as the building blocks of an electrically addressable memory technology, especially in the case of miniaturising towards the molecular scale and even single molecule devices. 4 The SCO phenomenon has been known about since the 1930s, 5 where it was discovered that certain compounds can undergo a transition between a high spin (HS) and low spin (LS) state via the application of
Jaafar, A. H., Marrows, C. H., Gee, A., Jaafar, A. H., Brachňaková, B., Massey, J., …Kemp, N. T. (2020). Multilevel Resistance Switching and Enhanced Spin Transition Temperature in Single- and Double-Molecule Spin Crossover Nanogap Devices. Journal of physical chemistry. C, 124(24), 13393-13399. https://doi.org/10.1021/acs.jpcc.0c03824
|Journal Article Type||Article|
|Acceptance Date||May 30, 2020|
|Online Publication Date||May 30, 2020|
|Publication Date||Jun 18, 2020|
|Deposit Date||Feb 9, 2021|
|Publicly Available Date||May 31, 2021|
|Journal||The Journal of Physical Chemistry C|
|Publisher||American Chemical Society|
|Peer Reviewed||Peer Reviewed|
|Keywords||Gold; Molecules; Electrodes; Quantum mechanics; Nanogaps|
|Related Public URLs||http://eprints.whiterose.ac.uk/161425/|
This file is under embargo until May 31, 2021 due to copyright reasons.
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