7 research outputs found
Rare earth contributions to the X-ray magnetic circular dichroism at the Co K edge in rare earth-cobalt compounds investigated by multiple-scattering calculations
The X-ray magnetic circular dichroism (XMCD) has been measured at the Co K
edge in Co-hcp and R-Co compounds (R=La, Tb, Dy). The structure of the
experimental XMCD spectra in the near-edge region has been observed to be
highly sensitive to the magnetic environment of the absorbing site.
Calculations of the XMCD have been carried out at the Co K edge in Co metal,
LaCo and TbCo within the multiple-scattering framework including the
spin-orbit coupling. In the three systems, the XMCD spectra in the near-edge
region are well reproduced. The possibility to separate and quantitatively
estimate the local effects from those due to the neighboring atoms in the XMCD
cross section makes possible a more physical understanding of the spectra. The
present results emphasize the major role played by the states of the Tb
ions in the XMCD spectrum at the Co K edge in the TbCo compound.Comment: 34 pages, revtex, 10 eps figures included with epsf, after referee
revie
Theory of Scanning Tunneling Spectroscopy of Magnetic-Field-Induced Discrete Nodal States in a D-Wave Superconductor
In the presence of an external magnetic field, the low lying elementary
excitations of a d-wave superconductor have quantized energy and their momenta
are locked near the node direction. It is argued that these discrete states can
most likely be detected by a local probe, such as a scanning tunneling
microscope. The low temperature local tunneling conductance on the Wigner-Seitz
cell boundaries of the vortex lattice is predicted to show peaks spaced as . The peak is anomalous, and it is present only
if the superconducting order parameter changes sign at certain points on the
Fermi surface. Away from the cell boundary, where the superfluid velocity is
nonzero, each peak splits, in general, into four peaks, corresponding to the
number of nodes in the order parameter.Comment: RevTeX 3.0, 4 pages, 3 figures (included