504 research outputs found

### Thermal switching of indirect interlayer exchange in magnetic multilayers

We propose a magnetic multilayer layout, in which the indirect exchange
coupling (IEC also known as RKKY) can be switched on and off by a slight change
in temperature. We demonstrate such on/off IEC switching in a Fe/Cr/FeCr-based
system and obtain thermal switching widths as small as 10--20~K, essentially in
any desired temperature range, including at or just above room temperature.
These results add a new dimension of tunable thermal control to IEC in magnetic
nanostructures, highly technological in terms of available materials and
operating physical regimes.Comment: 3 figures, Supplementary Inf

### Ferromagnetic resonance and interlayer exchange coupling in magnetic multilayers with compositional gradients

Ferromagnetic resonance (FMR) in magnetic multilayers of type F1/f/F2, where
two strongly ferromagnetic layers F1 and F2 are separated by a weakly magnetic
spacer f with a compositional gradient along its thickness, is investigated.
The method allows to detect the weak signal from the spacer in additional to
the more pronounced and readily measured signal from the outer
strongly-magnetic layers, and thereby study the properties of the spacer as
well as the interlayer exchange interaction it mediates. Variable temperature
FMR measurements, especially near the relevant Curie points, reveal a rich set
of properties of the exchange interactions in the system. The obtained results
are useful for designing and optimizing nanostructures with
thermally-controlled magnetic properties.Comment: 6 pages, 3 figure

### Negative parity states of $^{11}$B and $^{11}$C and the similarity with $^{12}C

The negative parity states of $^{11}$B and $^{11}$C were studied based on the
calculations of antisymmetrized molecular dynamics(AMD). The calculations well
reproduced the experimental strengths of Gamov-Teller(GT), $M1$ and monopole
transitions. We, especially, focused on the $3/2^-_3$ and $5/2^-_2$ states, for
which GT transition strengths were recently measured. The weak $M1$ and GT
transitions for the $3/2^-_3$ in $^{11}$B and $^{11}$C are described by a
well-developed cluster structure of $2\alpha$+$t$ and $2\alpha$+$^3$He,
respectively, while the strong transitions for the $5/2^-_2$ is characterized
by an intrinsic spin excitation with no cluster structure. It was found that
the $3/2^-_3$ state is a dilute cluster state, and its features are similar to
those of the $^{12}$C$(0^+_2)$ which is considered to be a gas state of three
$\alpha$ clusters.Comment: 10 pages, 4 figures, submitterd to Physical Review

### Matrix Factorizations and Homological Mirror Symmetry on the Torus

We consider matrix factorizations and homological mirror symmetry on the
torus T^2 using a Landau-Ginzburg description. We identify the basic matrix
factorizations of the Landau-Ginzburg superpotential and compute the full
spectrum, taking into account the explicit dependence on bulk and boundary
moduli. We verify homological mirror symmetry by comparing three-point
functions in the A-model and the B-model.Comment: 41 pages, 9 figures, v2: reference added, minor corrections and
clarifications, version published in JHE

### Cohomology Groups of Deformations of Line Bundles on Complex Tori

The cohomology groups of line bundles over complex tori (or abelian
varieties) are classically studied invariants of these spaces. In this article,
we compute the cohomology groups of line bundles over various holomorphic,
non-commutative deformations of complex tori. Our analysis interpolates between
two extreme cases. The first case is a calculation of the space of
(cohomological) theta functions for line bundles over constant, commutative
deformations. The second case is a calculation of the cohomologies of
non-commutative deformations of degree-zero line bundles.Comment: 24 pages, exposition improved, typos fixe

- âŠ