NOWNano DTC: The North West Nanoscience Doctoral Training Centre

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Research Projects

Can graphene be magnetic?

Supervisors

Dr Irina Grigorieva (School of Physics, University of Manchester)
Prof. Vladimir Falko (Physics Department, University of Lancaster)

 

Background

There has been much excitement in recent years about the reports of room-temperature ferromagnetism in pure carbon-based systems, such as highly-oriented pyrolytic graphite (HOPG), proton-irradiated carbon films and carbon nanofoams [1-3]. This is despite the absence of d- or f- electrons that are normally needed for the appearance of magnetism. After the discovery of graphene, with its unique properties, a question of possible ferromagnetism in this remarkable material arose as well and the first findings of room-temperature ferromagnetism have been reported recently [4]. If it is indeed possible to make graphene magnetic, it will be invaluable for applications in spintronics, the fast developing field where electron spins are exploited instead of the electron charge. However, the reports of (ferro-)magnetism in graphene remain highly controversial because so far is proved to be difficult to make macroscopic samples free of magnetic impurities and inclusions of bulk graphite, so it is quite possible that the observed magnetism is due to contamination rather than intrinsic.

The Project

The Manchester group have accumulated unrivalled expertise in preparation of ultra-pure graphene samples and devices, including macroscopic samples suitable for magnetisation measurements. Preliminary experiments on such samples have just been completed and revealed magnetic behaviour that cannot be simply explained by existing theories. The first stage of the project will involve extensive measurements on similar samples and the development of theory to understand the observed magnetism. The second stage of the project will involve investigation of the effect of the introduction of controlled defects and chemical modifications of graphene on its magnetic properties. This is an unexplored territory, but preliminary theoretical studies show that both the presence of defects and bonding of certain ionic groups to graphene may have a profound effect on magnetism.

Infrastructure and support
The Manchester group has unlimited access to all the facilities required for the implementation of the project, including a SQUID and VSM magnetometers, magnetic decoration technique, scanning probe microscopy and clean room facilities. The project will be supported by an EPSRC grant EP/G02491X/1. The modelling work lead by the Lancaster group is supported by the new high-performance computing facility which will reach top operation in March 2010 and will allow to perform numerical Monte Carlo simulations of thermodynamics properties of ensembles of magnetic atoms on graphene and its edges using 250 processors and analytical computation for small-size systems using 10 high-memory (64Gb per chip) processors embedded in the high-performance cluster. The student will also be supported by an RA already working at Lancaster.