373 research outputs found
Surface spin waves in superconducting and insulating ferromagnets
Surface magnetization waves are studied on a semi-infinite magnetic medium in
the perpendicular geometry. Both superconducting and insulating ferromagnets
are considered. Exchange and dipole energies are taken into account, as well as
retardation effects. At large wave vectors, the spectrum for a superconductor
and insulator is the same, though for the former the branch is terminated much
earlier than for the latter due to excitation of plasmons. At small wave
vectors, the surface wave is more robust in the superconductor since it is
separated from the bulk continuum by a finite gap.Comment: 4 pages, 2 figure
Triplet Josephson effect with magnetic feedback
We study AC Josephson effect in a superconductor-ferromagnet heterostructure
with a variable magnetic configuration. The system supports triplet proximity
correlations whose dynamics is coupled to the magnetic dynamics. This feedback
dramatically modifies the behavior of the junction. The current-phase relation
becomes double-periodic at both very low and high Josephson frequencies
. At intermediate frequencies, the periodicity in may be
lost.Comment: 4 pages, 3 figure
Fully developed triplet proximity effect
We present a model for fully developed triplet proximity effect in
superconductor-ferromagnet heterostructures.
Within the circuit-theory approximation, we evaluate the Green's functions,
the density of states, and the Josephson current that depend essentially on the
magnetization configuration.Comment: 4 pages, 4 figure
Microwave Response and Spin Waves in Superconducting Ferromagnets
Excitation of spin waves is considered in a superconducting ferromagnetic
slab with the equilibrium magnetization both perpendicular and parallel to the
surface. The surface impedance is calculated and its behavior near propagation
thresholds is analyzed. Influence of non-zero magnetic induction at the surface
is considered in various cases. The results provide a basis for investigation
of materials with coexisting superconductivity and magnetism by microwave
response measurements.Comment: 10 pages, 7 figure
Excitation of Spin Waves in Superconducting Ferromagnets
This Letter presents a theoretical analysis of propagation of spin waves in a
superconducting ferromagnet. The surface impedance was calculated for the case
when the magnetization is normal to the sample surface. We found the
frequencies at which the impedance and the power absorption have singularities
related to the spin wave propagation, and determined the form of these
singularities. With a suitable choice of parameters, there is a frequency
interval in which two propagating spin waves of the same circular polarization
are generated, one of them having a negative group velocity.Comment: 4 pages, 2 figures, submitted to PR
Selective single blastocyst transfer reduces the multiple pregnancy rate and increases pregnancy rates: a pre- and postintervention study
Magnetoresistive study of antiferromagnetic--weak ferromagnetic transition in single-crystal LaCuO
The resistive measurements were made to study the magnetic field-induced
antiferromagnetic (AF) - weak ferromagnetic (WF) transition in LaCuO
single-crystal. The magnetic field (DC or pulsed) was applied normally to the
CuO layers. The transition manifested itself in a drastic decrease of the
resistance in critical fields of ~5-7 T. The study is the first to display the
effect of the AF -WF transition on the conductivity of the LaCuO
single-crystal in the parallel - to - CuO layers direction. The results
provide support for the 3-dimensional nature of the hopping conduction of this
layered oxide.Comment: 8 pages, 7 figures, RevTe
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