Magnetic properties of PdAs2O6: a dilute spin system with an unusually high N\'eel temperature

The crystal structure and magnetic ordering pattern of PdAs2O6 were investigated by neutron powder diffraction. While the magnetic structure of PdAs2O6 is identical to the one of its isostructural 3d-homologue NiAs2O6, its N\'{e}el temperature (140 K) is much higher than the one of NiAs2O6 (30 K). This is surprising in view of the long distance and indirect exchange path between the magnetic Pd$^{2+}$ ions. Density functional calculations yield insight into the electronic structure and the geometry of the exchange-bond network of both PdAs2O6 and NiAs2O6, and provide a semi-quantitative explanation of the large amplitude difference between their primary exchange interaction parameters

Pressure-temperature phase diagram of SeO2. Characterization of new phases

We have investigated SeO2 at high pressures and high temperatures. Two new phases (beta-SeO2 and gamma-SeO2) and the boundary separating them have been found, following experimental runs performed at pressures tip to 15 GPa and temperatures up to 820degreesC. The two phases crystallize in the orthorhombic system in space group Pmc2(1) (no. 26) with a = 5.0722(1) Angstrom, b = 4.4704(1) Angstrom, c = 7.5309(2) Angstrom, V = 170.760(9) Angstrom(3) and Z = 4 for the beta-phase, and with a = 5.0710(2) Angstrom, b = 4.4832(2) Angstrom, c = 14.9672(6) Angstrom, V = 340.27(3) Angstrom(3) and Z = 8 for the gamma-phase. Both phases are stable at ambient pressure and temperature below -30degreesC. At ambient temperature the phases return to the starting phase (alpha-SeO2) in a few days. We discuss our findings in relation to a previous report of in-situ measurements at high pressures and ambient temperature. (C) 2004 Elsevier Inc. All rights reserved

Monopoly pricing in the binary herding model

How should a monopolist price when selling to buyers who learn from each other’s decisions? Focusing on the case in which the common value of the good is binary and each buyer receives a binary private signal about that value, we completely answer this question for all values of the production cost, the precision of the buyers’ signals, and the seller’s discount factor. Unexpectedly, we find that there is a region of parameters for which learning stops at intermediate and at extreme beliefs, but not at beliefs that lie between those intermediate and extreme beliefs

The Effect of Better Information on Income Inequality

Information system, Income inequality, Risk sharing markets, D80, J24, J30,