5,564 research outputs found
Some Notes on the Flora of Ontonagon County, Michigan
It has been the custom for some years with the forestry students of Iowa State College to spend one summer in camp to get practical field work. These camps have been in various places-Colorado, Minnesota, Michigan and the Appalachian Mountains. Along with the practical forestry work these students also do field work in botany along taxonomic and ecological lines. It has been possible therefore to make an intensive ecologic and floristic study of the region. This is one of a series of papers in which the flora has been discussed1
Severe Fermi Surface Reconstruction at a Metamagnetic-Transition in CaSrRuO (for )
We report an electrical transport study in CaSrRuO single
crystals at high magnetic fields (). For , the Hall constant
decreases sharply at an anisotropic metamagnetic (MM) transition
reaching its value for SrRuO at high fields. A sharp decrease in the
coefficient of the resistivity -term and a change in the structure of
the angular magnetoresistance oscillations (AMRO) for rotating in the
planes, confirms the reconstruction of the Fermi surface (FS). Our observations
and LDA calculations indicate a strong dependence of the FS on the Ca
concentration and suggest the coexistence of itinerant and localized electronic
states in single layered ruthenates.Comment: 5 pages, 4 fig
High Field de Haas - van Alphen Studies of the Fermi Surfaces of LaMIn (M = Co, Rh, Ir)
We report measurements of the de Haas - van Alphen effect on a series of
compounds, LaMIn (M = Co, Rh, Ir). The results show that each of the Co
and Ir Fermi surfaces (FSs) exhibit some portions that are two dimensional and
some portions that are three dimensional. The most two dimensional character is
exhibited in LaCoIn, less two dimensional behavior is seen in
LaIrIn, no part of Fermi surface of LaRhIn is found to have a two
dimensional character. Thus the two dimensionality of portions of the FSs is
largely determined by the d character of the energy bands while all of the
effective masses remain 1.2. This fact has implications for the causes
of the heavy fermion nature of superconductivity and magnetism in the Ce-based
compounds having the similar composition and structure. All of the measurements
were performed at the National High Magnetic Field Laboratory using either
cantilever magnetometry or field modulation methods.Comment: 10 pages, 4 figure
Hybridization gap and Fano resonance in SmB
We present results of Scanning Tunneling Microscopy and Spectroscopy (STS)
measurements on the "Kondo insulator" SmB. The vast majority of surface
areas investigated was reconstructed but, infrequently, also patches of varying
size of non-reconstructed, Sm- or B-terminated surfaces were found. On the
smallest patches, clear indications for the hybridization gap and
inter-multiplet transitions were observed. On non-reconstructed surface areas
large enough for coherent co-tunneling we were able to observe clear-cut Fano
resonances. Our locally resolved STS indicated considerable finite conductance
on all surfaces independent of their structure.Comment: 5 pages, 4 figure
Global distribution of the solar wind during solar cycle 23: ACE observations
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95439/1/grl26167.pd
Hidden one-dimensional electronic structure and non-Fermi liquid angle resolved photoemission line shapes of -MoO
We report angle resolved photoemission (ARPES) spectra of
-MoO, a layered metal that undergoes two charge density wave
(CDW) transitions at 109 K and 30 K. We have directly observed the ``hidden
one-dimensional (hidden-1d)'' Fermi surface and an anisotropic gap opening
associated with the 109 K transition, in agreement with the band theoretical
description of the CDW transition. In addition, as in other hidden-1d materials
such as NaMoO, the ARPES line shapes show certain anomalies, which
we discuss in terms of non-Fermi liquid physics and possible roles of disorder.Comment: 3 figures; Erratum added to include missed reference
Irreversible dynamics of the phase boundary in U(Ru0.9)Rh0.04)2Si2 and implications for ordering
We report measurements and analysis of the specific heat and magnetocaloric
effect at the phase boundary into the single magnetic field-induced phase
(phase II) of U(Ru{0.96}Rh{0.04})2Si2, which yield striking similarities to the
valence transition of Yb{1-x}YxInCu4. To explain these similarities, we propose
a bootstrap mechanism by which a structural distortion causes an electric
quadrupolar order parameter within phase II to become coupled to the
5f-electron hybridization, giving rise to a valence change at the transition.Comment: 4 pages including 4 figure
Optical evidence for a spin-filter effect in the charge transport of
We have measured the optical reflectivity of
as a function of temperature between 1.5 and 300
and in external magnetic fields up to 7 . The slope at the onset of the
plasma edge feature in increases with decreasing temperature and
increasing field but the plasma edge itself does not exhibit the remarkable
blue shift that is observed in the binary compound . The analysis of
the magnetic field dependence of the low temperature optical conductivity
spectrum confirms the previously observed exponential decrease of the
electrical resistivity upon increasing, field-induced bulk magnetization at
constant temperature. In addition, the individual exponential magnetization
dependences of the plasma frequency and scattering rate are extracted from the
optical data.Comment: submitted to Phys. Rev. Let
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