Abstract
Here we report the results of a multifrequency (∼9, 20, 34, 239.2, and 336 GHz) variable-temperature continuous wave (cw) and X-band (∼9 GHz) pulse electron spin resonance (ESR) measurement performed at cryogenic temperatures on potassium split graphene nanoribbons (GNRs). Important experimental findings include the following: (a) The multifrequency cw ESR data infer the presence of only carbon-related paramagnetic nonbonding states, at any measured temperature, with the g value independent of microwave frequency and temperature. (b) A linear broadening of the ESR signal as a function of microwave frequency is noticed. The observed linear frequency dependence of ESR signal width points to a distribution of g factors causing the non-Lorentzian line shape, and the g broadening contribution is found to be very small. (c) The ESR process is found to be characterized by slow and fast components, whose temperature dependences could be well described by a tunneling level state model. This work not only could help in advancing the present fundamental understanding on the edge spin (or magnetic)-based properties of GNRs but also pave the way to GNR-based spin devices.
Original language | English (US) |
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Pages (from-to) | 7615-7623 |
Number of pages | 9 |
Journal | ACS Nano |
Volume | 6 |
Issue number | 9 |
DOIs | |
State | Published - Sep 25 2012 |
Externally published | Yes |
Keywords
- edge spin
- electron spin relaxation rate
- electron spin resonance
- graphene nanoribbons
- tunneling level states
ASJC Scopus subject areas
- General Materials Science
- General Engineering
- General Physics and Astronomy