J Low Temp Phys (2010) 159: 284–287 DOI 10.1007/s10909-009-0131-5 New Approach to High-Pressure Nuclear Magnetic Resonance with Anvil Cells T. Meissner · S.K. Goh · J. Haase · B. Meier · D. Rybicki · P.L. Alireza Received: 22 July 2009 / Accepted: 1 December 2009 / Published online: 1 January 2010 © Springer Science+Business Media, LLC 2009 Abstract A novel approach that uses radio-frequency microcoils in the high-pressure region of anvil cells with Nuclear Magnetic Resonance (NMR) experiments is de- scribed. High-sensitivity Al NMR data at 70 kbar for Al metal are presented for the first time. An expected decrease in the Al Knight shift at 70 kbar is observed, as well as an unexpected change in the local charge symmetry at the Al nucleus. The latter is not predicted by chemical structure analysis under high pressure. Keywords NMR · High pressure · Microcoil 1 Introduction Nuclear Magnetic Resonance (NMR) is a versatile bulk probe for the study of physi- cal properties of materials by observing transitions among nuclear spin levels. A very important parameter for such studies is pressure as it enables one to tune the ground state of a material [1]. However, to study materials in anvil cells that allow for the highest pressures, a low signal-to-noise ratio (SNR) restricted a wider application of NMR for such studies [2] up to now. This was due to the fact that one has to work with a relatively small sample size that, in addition, is only a tiny part of the sensitive volume of the radio-frequency (RF) coil that is located near the high-pressure re- gion outside the anvil cell. The ensuing low filling factor deteriorates the SNR. Given T. Meissner · J. Haase ( ) · B. Meier · D. Rybicki Faculty of Physics and Earth Science, University of Leipzig, 04103 Leipzig, Germany e-mail: j.haase@physik.uni-leipzig.de S.K. Goh · P.L. Alireza Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, UK P.L. Alireza Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK