Experts from the University of Sheffield have shed new light on the application of Nuclear Magnetic Resonance (NMR) on a nano scale, paving the way for improved medical imaging techniques, computing, telecommunications, data storage and photovoltaics.
The research, which was published today (28 August 2011) in Nature Materials looks at Nuclear Magnetic Resonance and has shown that it is possible to effectively and quickly control single nano-structures made of as small as 105-106 atoms that have sizes of just a few nanometres (1 nm is 10-9m), using electro-magnetic excitation.
NMR is widely used in medicine for Magnetic Resonance Imaging (MRI), a non-invasive imaging technique which allows doctors to obtain scans of various human organs. Unlike in a human body where NMR is used to look at organs of macroscopic sizes from a few millimetres up to a few centimetres with many trillions of nuclei (from 1020 to 1025), this research uses NMR on a much more detailed scale.
All nuclei in the samples used by the team possessed magnetic moments, which could be thought of as small magnets. When such magnets are aligned inside nano-structure using optical techniques, they create a very large magnetic field about 1 Tesla, about 10,000 times bigger than the magnetic field of the Earth. This field is concentrated inside the nano-structure. In order to generate such large fields on the macroscopic scale, special coils are used through which very high electrical currents are passed.
The team, led by Dr Alexander Tartakovskii from the University of Sheffield´s Department of Physics and Astronomy, have shown that it is possible to manipulate such large magnetic fields using fast radio-frequency pulses on a micro-second time scale. Previously such fields could only be controlled on a significantly longer timescale of a few seconds or longer.
The results pave the way for application of NMR on the nano-scale, something that could enable new powerful non-invasive techniques necessary for understanding of the nano-world.
Fabrication and understanding of semiconductor nano-structures is also key for important technological developments such as new types of computing based on quantum bits and improvements in telecommunications, data storage, medical markers and photovoltaics for renewable energy.
Dr Alexander Tartakovskii from the University of Sheffield, said: “Future technology will strongly depend on our understanding of the processes occurring on the nano-scale, be that in solids or liquids, in monolithic devices used in computers, data storage and photovoltaics, or in individual nano-structures, used as markers in medical applications.
“Our work moves the boundary of control and understanding of the nano-world as we have developed a potentially powerful technique for characterisation and probing of nano-structures. Importantly, our method is non-invasive: it allows us access to internal properties of the sample without physically breaking or changing it, much like it is done in MRI scans used in hospitals.”