Giant Dielectric Permittivity of Electron-Doped Manganite Thin Films, Ca(1-x)La(x)MnO(3) ($0<= x<= 0.03)

A giant low-frequency, in-plane dielectric constant, eps~10^6, for epitaxial thin films of Ca(1-x)La(x)MnO(3) (x<=0.03) was observed over a broad temperature range, 4K <= T 300K. This phenomenon is attributed to an internal barrier-layer capacitor (IBLC) structure, with insulating boundaries between semiconducting grains. The room-temperature eps increases substantially with electron (La) doping. The measured values of eps exceed those of conventional two-phase IBLC materials based on (Ba,Sr)TiO(3) as well as recently discovered CaCu(3)Ti(4)O(12) and (Li,Ti) doped NiO.Comment: 5 pages, 4 fig.s, J. Appl. Phys., Jan. 15, 2005 (in press

Nongassing NiCd battery cell

Method of constructing nickel cadmium batteries prevents excessive gas buildup and allows hermetic sealing of battery for increased service life and reduced maintenance cost

Several new catalysts for reduction of oxygen in fuel cells

Test results prove nickel carbide or nitride, nickel-cobalt carbide, titanium carbide or nitride, and intermetallic compounds of the transition or noble metals to be efficient electrocatalysts for oxygen reduction in alkaline electrolytes in low temperature fuel cells

Extreme thermopower anisotropy and interchain transport in the quasi-one-dimensional metal Li(0.9)Mo(6)O(17)

Thermopower and electrical resistivity measurements transverse to the conducting chains of the quasi-one-dimensional metal Li(0.9)Mo(6)O(17) are reported in the temperature range 5 K = 400 K the interchain transport is determined by thermal excitation of charge carriers from a valence band ~ 0.14 eV below the Fermi level, giving rise to a large, p-type thermopower that coincides with a small, n-type thermopower along the chains. This dichotomy -- semiconductor-like in one direction and metallic in a mutually perpendicular direction -- gives rise to substantial transverse thermoelectric (TE) effects and a transverse TE figure of merit among the largest known for a single compound.Comment: PRL in press, manuscript (5pp, 4 Fig.'s) and Supplementary Material (3pp, 3 Fig.'s

Hole Localization in Underdoped Superconducting Cuprates Near 1/8th Doping

Measurements of thermal conductivity versus temperature over a broad range of doping in YBa$_2$Cu$_3$O$_{6+x}$ and HgBa$_2$Ca$_{n-1}$Cu$_n$O$_{2n+2+\delta}$ ($n$=1,2,3) suggest that small domains of localized holes develop for hole concentrations near $p$=1/8. The data imply a mechanism for localization that is intrinsic to the CuO$_2$-planes and is enhanced via pinning associated with oxygen-vacancy clusters.Comment: 4 pages, 4 eps fig.'s, to be published, Phys. Rev.

Local Thermal Equilibrium in Quantum Field Theory on Flat and Curved Spacetimes

The existence of local thermal equilibrium (LTE) states for quantum field theory in the sense of Buchholz, Ojima and Roos is discussed in a model-independent setting. It is shown that for spaces of finitely many independent thermal observables there always exist states which are in LTE in any compact region of Minkowski spacetime. Furthermore, LTE states in curved spacetime are discussed and it is observed that the original definition of LTE on curved backgrounds given by Buchholz and Schlemmer needs to be modified. Under an assumption related to certain unboundedness properties of the pointlike thermal observables, existence of states which are in LTE at a given point in curved spacetime is established. The assumption is discussed for the sets of thermal observables for the free scalar field considered by Schlemmer and Verch.Comment: 16 pages, some minor changes and clarifications; section 4 has been shortened as some unnecessary constructions have been remove

Superconformal Primary Fields on a Graded Riemann Sphere

Primary superfields for a two dimensional Euclidean superconformal field theory are constructed as sections of a sheaf over a graded Riemann sphere. The construction is then applied to the N=3 Neveu-Schwarz case. Various quantities in the N=3 theory are calculated and discussed, such as formal elements of the super-Mobius group, and the two-point function.Comment: LaTeX2e, 23 pages; fixed typos, sorted references, modified definition of primary superfield on page

Ballistic magnon heat conduction and possible Poiseuille flow in the helimagnetic insulator Cu2_2OSeO3_3

We report on the observation of magnon thermal conductivity $\kappa_m\sim$ 70 W/mK near 5 K in the helimagnetic insulator Cu$_2$OSeO$_3$, exceeding that measured in any other ferromagnet by almost two orders of magnitude. Ballistic, boundary-limited transport for both magnons and phonons is established below 1 K, and Poiseuille flow of magnons is proposed to explain a magnon mean-free path substantially exceeding the specimen width for the least defective specimens in the range 2 K $<T<$ 10 K. These observations establish Cu$_2$OSeO$_3$ as a model system for studying long-wavelength magnon dynamics.Comment: 10pp, 9 figures, accepted PRB (Editor's Suggestion

Factorizations of Elements in Noncommutative Rings: A Survey

We survey results on factorizations of non zero-divisors into atoms (irreducible elements) in noncommutative rings. The point of view in this survey is motivated by the commutative theory of non-unique factorizations. Topics covered include unique factorization up to order and similarity, 2-firs, and modular LCM domains, as well as UFRs and UFDs in the sense of Chatters and Jordan and generalizations thereof. We recall arithmetical invariants for the study of non-unique factorizations, and give transfer results for arithmetical invariants in matrix rings, rings of triangular matrices, and classical maximal orders as well as classical hereditary orders in central simple algebras over global fields.Comment: 50 pages, comments welcom