3 research outputs found
Observation of a pressure-induced transition from interlayer ferromagnetism to intralayer antiferromagnetism in Sr4Ru3O10
Sr4Ru3O10 is a Ruddlesden-Popper compound with triple Ru-O perovskite layers
separated by Sr-O alkali layers. This compound presents a rare coexistence of
interlayer (c-axis) ferromagnetism and intralayer (basal-plane) metamagnetism
at ambient pressure. Here we report the observation of pressure-induced,
intralayer itinerant antiferromagnetism arising from the interlayer
ferromagnetism. The application of modest hydrostatic pressure generates an
anisotropy that causes a flattening and a tilting of RuO6 octahedra. All
magnetic and transport results from this study indicate these lattice
distortions diminish the c-axis ferromagnetism and basal-plane metamagnetism,
and induce a basal-plane antiferromagnetic state. The unusually large
magnetoelastic coupling and pressure tunability of Sr4Ru3O10 makes it a unique
model system for studies of itinerant magnetism.Comment: 6 figure
On the Penrose inequality
The purpose of this letter is to point out an argument which may ultimately
lead to a rigorous proof of the Penrose inequality in the general case. The
argument is a variation of Geroch's original proposal for a proof of the
positive energy theorem which was later adapted by Jang and Wald to apply to
initial data sets containing apparent horizons. The new input is to dispense
with the a priori restriction to an initial data set and to use the
four-dimensional structure of spacetime in an essential way.Comment: LaTeX. 5 pages, uses RevTe