356 research outputs found
Magnetism in purple bronze LiMoO
Muon spin relaxation measurements around the 25 K metal-insulator transition
in LiMoO elucidate a profound role of disorder as a possible
mechanism for this transition. The relaxation rate and the muon Knight
shift are incompatible with the transition to a SDW state and thus exclude it.Comment: pages 2, fig 2, The conf. on strongly correlated electron systems,
SCES 2004, German
Perspective: Strongly correlated and topological states in [111] grown transition metal oxide thin films and heterostructures
We highlight recent advances in the theory, materials fabrication, and
experimental characterization of strongly correlated and topological states in
[111] oriented transition metal oxide thin films and heterostructures, which
are notoriously difficult to realize compared to their [001] oriented
counterparts. We focus on two classes of complex oxides, with the chemical
formula ABO3 and A2B2O7, where the B sites are occupied by an open-shell
transition metal ion with a local moment, and the A sites are typically a rare
earth. The [111] oriented quasi-two-dimensional lattices derived from these
parent compound lattices can exhibit peculiar geometries and symmetries,
namely, a buckled honeycomb lattice, as well as kagome and triangular lattices.
These lattice motifs form the basis for emergent strongly correlated and
topological states expressed in exotic magnetism, various forms of orbital
ordering, topological insulators, topological semimetals, quantum anomalous
Hall insulators, and quantum spin liquids. For transition metal ions with high
atomic number, spin-orbit coupling plays a significant role and may give rise
to additional topological features in the electronic band structure and in the
spectrum of magnetic excitations. We conclude the Perspective by articulating
open challenges and opportunities in this actively developing field
Local Magnetic Susceptibility of the Positive Muon in the Quasi 1D S=1/2 Antiferromagnet KCuF
We report muon spin rotation measurements of the local magnetic
susceptibility around a positive muon in the paramagnetic state of the quasi
one-dimensional spin 1/2 antiferromagnet KCuF. Signals from two distinct
sites are resolved which have a temperature dependent frequency shift which is
different than the magnetic susceptibility. This difference is attributed to a
muon induced perturbation of the spin 1/2 chain.Comment: 13 pages, 4 figures, The 2002 International Conference on Muon Spin
Rotation, Relaxation and Resonance, Virginia. US
Emergent properties hidden in plane view: Strong electronic correlations at oxide interfaces
Finding new collective electronic states in materials is one of the
fundamental goals of condensed matter physics. Atomic-scale superlattices
formed from transition metal oxides are a particularly appealing hunting ground
for new physics. In bulk form, transition metal oxides exhibit a remarkable
range of magnetic, superconducting, and multiferroic phases that are of great
scientific interest and are potentially capable of providing innovative energy,
security, electronics and medical technology platforms. In superlattices new
states may emerge at the interfaces where dissimilar materials meet.
Here we illustrate the essential features that make transition metal
oxide-based heterostructures an appealing discovery platform for emergent
properties with a few selected examples, showing how charge redistributes,
magnetism and orbital polarization arises and ferroelectric order emerges from
heterostructures comprised of oxide components with nominally contradictory
behavior with the aim providing insight into the creation and control of novel
behavior at oxide interfaces by suitable mechanical, electrical or optical
boundary conditions and excitations.Comment: 16 pages, 5 figure
On Magnetic Interlayer Coupling and Proximity Effect in a LaCaMnO(10 nm)/YBaCuO(10 nm) Superlattice
We present a study of interlayer coupling and proximity effects in a
LaCaMnO(10 nm)/YBaCuO(10 nm) superlattice.
Using element-sensitive x-ray probes, the magnetic state of Mn can be probed
without seeing the strong diamagnetism of the superconductor, which makes this
approach ideal to study changes in the magnetic properties across the
superconducting transition. By a combined experiment using {\it in situ}
transport measurements during polarized soft x-ray measurements, we were able
to see no noticeable influence of the superconducting state on the magnetic
properties and no evidence for magnetic coupling across a 10 nm YBCO layer.Comment: 4 pages, submitted to Applied Physics Letter
Effect of polar discontinuity on the growth of LaNiO3/LaAlO3 superlattices
We have conducted a detailed microscopic investigation of [LaNiO3(1
u.c.)/LaAlO3(1 u.c.)]N superlattices grown on (001) SrTiO3 and LaAlO3 to
explore the influence of polar mismatch on the resulting electronic and
structural properties. Our data demonstrate that the initial growth on the
non-polar SrTiO3 surface leads to a rough morphology and unusual 2+ valence of
Ni in the first LaNiO3 layer, which is not observed after growth on the polar
surface of LaAlO3. A newly devised model suggests that the polar mismatch can
be resolved if the perovskite layers grow with an excess of LaO, which also
accounts for the observed electronic, chemical, and structural effects.Comment: 3 pages, 3 figure
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