Applications of nuclear probe techniques to materials science

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Nuclear magnetic resonance (NMR) is one of the most powerful analytical tools in the fields of physics, chemistry, biology and medical sciences. Nevertheless, the NMR method suffers from a low sensitivity that limits its applicability. In recent years it has been demonstrated that high nuclear-spin polarization of xenon gas can be achieved by optical pumping methods. The hyperpolarized xenon may be used for novel NMR experiments that require enhanced sensitivity and selectivity. We are pursuing one such application, namely, enhanced solid-state NMR spectroscopy for the study of magnetism at sample surfaces. Such experimental investigations are highly relevant for emerging areas such as magnetic nanotechnology. We also study magnetism deep inside materials using tiny subatomic particles called 'muons'. In recent years we have applied this method to the study of magnetic flux lines, called 'vortices', in superconducting materials. The fundamental results from these studies are significant for scientific and technological applications, ranging from electrical power transmission to medical imaging. In the near future we will apply this method to the study of competing magnetic and superconducting phases in unconventional systems. We will also use muons to study new classes of magnets based on molecular chemistry. The scientific outcome of our work will contribute to the knowledge base that will one day lead to new magnetic devices based on 'molecular' rather than traditional 'atomic' magnetic building blocks. While the number of elements in the periodic table is limited to one hundred or so, there are several million organic compounds. Thus molecular magnetism offers an unprecedented flexibility in the design of magnetic materials, and accordingly is an area of research that is attracting increasing interest.