279 research outputs found
How experimentally to detect a solitary superconductivity in dirty ferromagnet-superconductor trilayers?
We theoretically study the proximity effect in the thin-film layered
ferromagnet (F) - superconductor (S) heterostructures in FFS design. We
consider the boundary value problem for the Usadel-like equations in the case
of so-called "dirty" limit. The "latent" superconducting pairing interaction in
F layers taken into account. The focus is on the recipe of experimental
preparation the state with so-called solitary superconductivity. We also
propose and discuss the model of the superconducting spin valve based on
FFS trilayers in solitary superconductivity regime
Whirling spin order in the quasicrystal approximant AuAlTb
Neutron powder diffraction experiment has been performed on the quasicrystal
approximant AuAlTb, a body-center-cubic crystal of
icosahedral spin clusters. The long-range antiferromagnetic order was confirmed
at the transition temperature K. The magnetic structure
consists of noncoplanar whirling spins on the icosahedral clusters, arranging
antiferroic-manner. A simple icosahedral spin-cluster model with uniaxial
anisotropy accounts well the whirling spin order as well as the in-field
metamagnetic transition, indicating that the icosahedral symmetry is essential.Comment: 6 pages, 4 figure
The ferroelectric phase of CdTiO3. A powder neutron diffraction study.
The synthesis of bulk samples of polycrystalline CdTiO3 in both the rhombohedral ilmenite and orthorhombic perovskite forms is described and the structures of these have been refined using powder neutron diffraction data. This involved the preparation of samples enriched in Cd-114. Cooling perovskite-type CdTiO3 to 4 K induces a ferroelectric phase transition, with the neutron data suggesting the low temperature structure is in Pna21. Mode analysis shows the polar mode to be dominant at low temperatures. The ilmenite-structure of CdTiO3 is compared with that of ZnTiO3. The refined scattering length of the Cd-114 is estimated to be 5.56 fm.Australian Research Counci
Understanding the cation ordering transition in high-voltage spinel LiNi0.5Mn1.5O4 by doping Li instead of Ni
We determined how Li doping affects the Ni/Mn ordering in high-voltage spinel LiNi0.5Mn1.5O4(LNMO) by using neutron diffraction, TEM image, electrochemical measurements, and NMR data. The doped Li occupies empty octahedral interstitials (16c site) before the ordering transition, and can move to normal octahedral sites (16d (4b) site) after the transition. This movement strongly affects the Ni/Mn ordering transition because Li at 16c sites blocks the ordering transition pathway and Li at 16d (4b) sites affects electrostatic interactions with transition metals. As a result, Li doping increases in the Ni/Mn disordering without the effect of Mn3+ ions even though the Li-doped LNMO undergoes order-disorder transition at 700 degrees C. Li doping can control the amount of Ni/Mn disordering in the spinel without the negative effect of Mn3+ ions on the electrochemical property.111Ysciescopu
- β¦