78 research outputs found
Spin Susceptibility and Superexchange Interaction in the Antiferromagnet CuO
Evidence for the quasi one-dimensional (1D) antiferromagnetism of CuO is
presented in a framework of Heisenberg model. We have obtained an experimental
absolute value of the paramagnetic spin susceptibility of CuO by subtracting
the orbital susceptibility separately from the total susceptibility through the
Cu NMR shift measurement, and compared directly with the theoretical
predictions. The result is best described by a 1D antiferromagnetic
Heisenberg (AFH) model, supporting the speculation invoked by earlier authors.
We also present a semi-quantitative reason why CuO, seemingly of 3D structure,
is unexpectedly a quasi 1D antiferromagnet.Comment: 7 pages including 4 tables and 9 figure
ARPES: A probe of electronic correlations
Angle-resolved photoemission spectroscopy (ARPES) is one of the most direct
methods of studying the electronic structure of solids. By measuring the
kinetic energy and angular distribution of the electrons photoemitted from a
sample illuminated with sufficiently high-energy radiation, one can gain
information on both the energy and momentum of the electrons propagating inside
a material. This is of vital importance in elucidating the connection between
electronic, magnetic, and chemical structure of solids, in particular for those
complex systems which cannot be appropriately described within the
independent-particle picture. Among the various classes of complex systems, of
great interest are the transition metal oxides, which have been at the center
stage in condensed matter physics for the last four decades. Following a
general introduction to the topic, we will lay the theoretical basis needed to
understand the pivotal role of ARPES in the study of such systems. After a
brief overview on the state-of-the-art capabilities of the technique, we will
review some of the most interesting and relevant case studies of the novel
physics revealed by ARPES in 3d-, 4d- and 5d-based oxides.Comment: Chapter to appear in "Strongly Correlated Systems: Experimental
Techniques", edited by A. Avella and F. Mancini, Springer Series in
Solid-State Sciences (2013). A high-resolution version can be found at:
http://www.phas.ubc.ca/~quantmat/ARPES/PUBLICATIONS/Reviews/ARPES_Springer.pdf.
arXiv admin note: text overlap with arXiv:cond-mat/0307085,
arXiv:cond-mat/020850
A high-pressure study of by X-ray diffraction and synchrotron radiation. 1. Pressures up to 38.6 GPa
High-pressure X-ray diffraction studies have been performed on powder samples of [beta]-Ti3O5 (C2/m) for pressures up to 38.6 GPa using synchrotron radiation and a diamond-anvil cell. The compressibility is highly anisotropic. Thus, the compression [Delta]l/l0 for the maximum pressure investigated is 5.4, 0.8 and 6.7% for the unit-cell axis directions a, b and c, respectively. The anisotropy is reasonable, considering the crystal structure. The bulk modulus B%_0%, determined from the Murnaghan equation, is 173(10) GPa and B'0 is 7(1)
A high-pressure single-crystal X-ray diffraction study of copper oxide using synchrotron radiation
The crystal structure and lattice parameters of single crystal CuO have been studied up to 80 kbar using a new high-pressure diamond anvil cell and synchrotron radiation
A high-pressure single-crystal X-ray diffraction study of copper oxide using synchrotron radiation
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