1,542 research outputs found
Anisotropic softening of magnetic excitations in lightly electron doped SrIrO
The magnetic excitations in electron doped (SrLa)IrO with
were measured using resonant inelastic X-ray scattering at the Ir
-edge. Although much broadened, well defined dispersive magnetic
excitations were observed. Comparing with the magnetic dispersion from the
parent compound, the evolution of the magnetic excitations upon doping is
highly anisotropic. Along the anti-nodal direction, the dispersion is almost
intact. On the other hand, the magnetic excitations along the nodal direction
show significant softening. These results establish the presence of strong
magnetic correlations in electron doped SrLa)IrO with close
analogies to the hole doped cuprates, further motivating the search for high
temperature superconductivity in this system
Doping Evolution of Magnetic Order and Magnetic Excitations in (SrLa)IrO
We use resonant elastic and inelastic X-ray scattering at the Ir- edge
to study the doping-dependent magnetic order, magnetic excitations and
spin-orbit excitons in the electron-doped bilayer iridate
(SrLa)IrO (). With increasing
doping , the three-dimensional long range antiferromagnetic order is
gradually suppressed and evolves into a three-dimensional short range order
from to , followed by a transition to two-dimensional short range
order between and . Following the evolution of the
antiferromagnetic order, the magnetic excitations undergo damping, anisotropic
softening and gap collapse, accompanied by weakly doping-dependent spin-orbit
excitons. Therefore, we conclude that electron doping suppresses the magnetic
anisotropy and interlayer couplings and drives
(SrLa)IrO into a correlated metallic state hosting
two-dimensional short range antiferromagnetic order and strong
antiferromagnetic fluctuations of moments, with
the magnon gap strongly suppressed.Comment: 6 Pages, 3 Figures, with supplementary in Sourc
The lithospheric mantle and lower crust-mantle relationships under Scotland: a xenolithic perspective
In the British Isles the majority of volcanic rocks containing upper mantle and lower crustal xenoliths occur in Scotland. Most of the occurrences are of Carboniferous–Permian age. This paper presents new data on the mineral chemistry of spinel lherzolite xenoliths from the five principal Scottish tectonic terranes. Compositional variations among the minerals emphasize the broad lateral heterogeneity of the subcontinental lithospheric mantle across the region. The remarkable range of Al2O3 v. CaO exhibited by the clinopyroxenes compared with data from other ‘xenolith provinces' emphasizes the extremely complex tectonomagmatic history of the Scottish lithosphere. The generalized age increase from southern and central Scotland to the Northern Highland and Hebridean terranes of the north and NW, with concomitant complexity of geological history, is reflected also by trace element and isotopic studies. Reaction relationships in lherzolites from the Hebridean Terrane, owing to pervasive metasomatism, involve secondary growth of sodic feldspar. This, and light REE enrichment of clinopyroxenes, points to involvement of a natro-carbonatitic melt. Most pyroxenitic xenoliths are inferred to form a basal crustal layer with a generally sharp discontinuity above the underlying (dominantly lherzolitic) mantle. A second discontinuity is inferred to separate these ultramafic cumulates from overlying, broadly cognate metagabbroic cumulates
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