Search

We discuss the different free energies and Hamiltonians for materials in static electric and magnetic fields and which choice is the most appropriate for statistical mechanics calculations. We also discuss the relation between the various free energies and the Landau function which has to be minimized to determine the equilibrium polarization or magnetization.

Determination of resistivity, Hall effect and Shubnikov-de Hass (SdH) oscillatory magnetoresistance help analyze the gate voltage dependent charge distribution in the subbands of delta-doped In(0.29)-Al(0.71)As / In(0.3)Ga(0. 7)As heterostructures. Hall measurement reveals the development of an apparent electron density due to delta-doping. The barrier layer with Si and SdH spectra shows a gate voltage-dependent transition from one subband to two subbands. Fast Fourier transforms of the SdH data and low field magnetoresistance data help determine electron densities and mobilities of the two subbands at V(g) = O.

Giant magnetoresistance (GMR) in heterogenous Cu-Co and Ag-Co alloy thin films was investigated. The results showed that GMR in the Ag-Co sample was greater than that in the Ag-Co film. This was attributed to the smaller amount of dissolved Co in the Ag matrix. In addition, GMR was inversely proportional to the precipitate particle size. This indicated that Co-rich clusters with sizes greater than or equal to 20 angstroms were most effective for spin dependent scattering.

A study of the structure factor and correlation length of a spin-1/2 Heisenberg antiferromagnet revealed that the spin stiffness was of a higher magnitude in the square lattice than in the triangular lattice. A semiclassical spin-wave picture did not delineate the ground state of the triangular lattice, which was proximal to the quantum critical point.

The aim of this article is to explore the practical complexity of accountability in health care by focusing on a particular crisis affecting one NHS trust in the UK, that of insufficient beds to meet demand. It is presented through the eyes of five middle managers with nursing backgrounds. Although the focus is on their words, their expressions of distress and their awareness of conflict, these lead to a commentary highlighting some of the relationships between theory and practice, policy making and implementation, and, in the final analysis, compulsion and choice. The managers seemed to work within four main patterns of provider accountability: public, professional, pecuniary and personal. These four Ps of accountability created incompatibilities in the accountability process, but the conclusion attempts to draw the threads together to suggest a possible way forward. In order to protect confidentiality, pseudonyms are used for the NHS trust and the interviewees, and some personal details have been disguised. [ABSTRACT FROM AUTHOR]

Presents news briefs concerning environmental conferences as of October 1981. Inclusion of the meeting of the Committee on Water Problems of the Economic Commissions for Europe (ECE), held in Geneva, Switzerland; Third International Cadmium Conference, held in Miami, Florida.

Investigates the magnetotransport properties of asymmetric double quantum well heterostructures. Charge transport parameters prior to and following an optically induced ionization of the DX centers; Impact of the delta-doped layer embedded within a gallium arsenide well; Illumination in the quantum well and in embedded gallium arsenide well.

Examines the presence of giant magnetoresistance in heterogeneous AgCo alloy thin films. Analysis of Co-rich precipitates in an Ag-rich matrix; Dependence of magnetoresistance on Co concentration and particle size; Impact of annealing on magnetoresistance.