Magnetic Properties of Hydrogen‐Terminated Surface Layer of Diamond Nanoparticles

Abstract

Nanodiamonds (ND) with the mean size about 4–5 nm is an interesting object for studying electronic and magnetic properties of diamond surface throughout its high specific area. Chemically modified ND particle is a very promising new unique material for applications in molecular nano‐electronics. Results of recent magnetic studies of pristine and hydrogen‐terminated ND samples, obtained by detonation technique, are reported and discussed. In addition to characteristic structural defects, originating from dangling C–C bonds of sp³ sites and located mainly in the interior of the nanocrystals, the hydrogen‐terminated ND crystals show a high concentration of excess free radicals (up to 10²¹ spin/g), which are due to structural defects (dangling C–C bonds) induced on the surface of diamond nanocrystals by hydrothermal treatment. Strong antiferromagnetic coupling is found between the spins localized on the surface.

Keywords:

• Diamond nanoparticle
• surface modification
• dangling bond
• localized spins
• magnetic susceptibility
• antiferromagnetism
• low temperatures
• SQUID

Acknowledgments

The present work is supported by the Grant‐in‐Aid for Scientific Research No. 15105005 from the Japanese Society for the Promotion of Science (JSPS). V.Yu.O. and M.V.B. thank Japanese Society for the Promotion of Science and Tokyo Institute of Technology (Japan) for the fellowship and financial support. A.Ya.V. thanks the Russian Federal Agency for Science and Innovation for the financial support (grant 02.435.11.2013).