Fe–Co alloys in the α phase are soft magnetic materials which have high saturation inductions over a wide range of compositions. However, above about 1250 K, an α to γ phase transition occurs. The fcc-based, γ, high-temperature phase is paramagnetic at this temperature. In this work the low-temperature ordered B2, or α′, phase, as well as the disordered bcc phase of FeCo alloys, have been studied with first-principles electronic-structure calculations using the layer Korringa–Kohn–Rostoker method. The variation of moment with composition (Slater–Pauling curve) is discussed. For equiatomic FeCo, interatomic exchange couplings are derived from first principles. These exchange interactions are compared to those obtained for pure Fe and Co, and are used within a mean-field theory to estimate the hypothetical Curie temperature of the α phase.

We search for neutral heavy leptons that are isosinglets under the standard SU (2)l gauge group. Such neutral heavy leptons are expected in many extensions of the standard model. Three types of heavy leptons Ne, N^, NT associated with the three neutrino types v* have been directly searched for and no evidence for a signal has been found. We set the limit Br(Z° -► z//N*) < 3 x 10" 5 at the 95% CL for the mass range from 3 GeV up to m%.

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We present a study of 43 000 3-jet events from Z° boson decays. Both the measured jet energy distributions and the event orientation are reproduced by second order QCD. An alternative model with scalar gluons fails to describe the data.