SµS - Swiss Muon Source
NUM / LMU SEMINAR
Other seminars / events at PSI:
for Neutron Scattering (NUM/LNS)
All Departments (PSI event calendar)
Date: Friday, August 30, 2013
Room: WBGB/019, PSI West
Magnetism of Cerium Dioxide Nanoparticles
Mr. Karl Ackland
School of Physics and CRANN, Trinity College, Dublin 2, Ireland
Room temperature ferromagnetism in CeO2 nanoparticles, in the absence of any known ferromagnetic constituents, may be a case of "d0" magnetism, in which ferromagnetism is believed to be induced by crystal defects . Defects in these materials are thought to be critical for the appearance of magnetism, since well-crystallized, defect-free bulk material is never magnetic. Their role, whether it is to stabilize localized spin moments, create a defect-based impurity band, or mediate exchange interactions remains a subject of debate.
Here an introduction to the phenomenon of d0 magnetism is first presented, followed by some experimental results for magnetism is CeO2 nanoparticles. Some characteristics of the magnetism are that it is virtually anhysteretic, isotropic and temperature independent in the range 4 â€“ 300 K. It may be estimated that only of order 0.1 % of the sample volume is magnetically ordered, consistent with inhomogeneous defect magnetism associated with interfaces or surfaces. Finally, plans for bulk Î¼SR measurements of this material at PSI are discussed.
 J. M. D. Coey, et al., New Journal of Physics 12, 053025 (2010).
Paul Scherrer Institute
Villigen PSI, Switzerland
to get to PSI