No description available.

<p> [Co/Pd]<i>_n</i> multilayers with different number of repetitions n were deposited on Si substrates in order to study the magnetic properties and Hall resistivity in this system. The magnetic moment dependence on applied field was studied in parallel (in-plane) and perpendicular (out-of-plane) configurations. The [Co/Pd]<i>_n</i> multilayers with 2 and 3 repetitions, with thickness of the Co sublayer of 0.8 and 1.0 nm and thickness of the Pd sublayer of 1.3 and 2.0 nm, were found to have perpendicular magnetic anisotropy. The Hall resistivity dependence on applied field was measured at different temperatures. The Hall hysteresis loops confirm the perpendicular anisotropy of the multilayers, and indicate that the origin of the anomalous Hall effect (AHE) in this system, with low number of repetitions, is dominated by surface scattering.</p>

The CPLEAR experiment is a high precision experiment aiming to measure several CP violating parameters in the neutral kaon system. In order to decouple the errors on the phase angles of these parameters with the error on the KL- Ks mass difference (~m), the experiment will also make a measurement of ~m from semileptonic neutral kaon decays. This thesis describes a preliminary determination of ~m from a time dependent asymmetry in the semileptonic decays of tagged KOs and KOs. In order to select a sample of semileptonic decays it was necessary to develop a method of separating electron and pion tracks. The electromagnetic calorimeter can only separate electrons and pions at momenta above 200 MeVIc. In this thesis the development of a method of separating the two types of particle at momenta below 250 MeV[c is also described. From data collected between September 1990 and October 1991, a sample of 45000 semileptonic decays has been isolated and a value of the mass difference determined to be ~mhs = 0.477 ± 0.016(stat.) +-00..000014 } (syst.)

We present a microscopic model of the high temperature superconductors which provides evidence for non-Fermi liquid behaviour. Starting from the Anderson Lattice model, we derive a three-band model of a CU02 plane. We show that the popular t-J model is a subset of our model under certain assumptions which we show to be unphysical. We study the three-band model on the CuO chain. Using two exact solutions of the model to provide trial variational states, and comparing these with an exact finite system numerical calculation, we demonstrate that the spin degeneracy is lifted by the hole motion alone. This provides Heisenberg spin correlations for a physical choice of parameters, and the system is found to be a Luttinger liquid. In two dimensions we numerically solve a series of systems which limit to the CU02 plane. We predict that the CU02 planes will exhibit a highly quantum ground state dominated by short-range dimer correlations, reminiscent of a resonating valence bond state. These predictions are contrary to those of the t-J model, where the hole motion alone predicts huge spin degeneracy for the linear chain, and Nagaoka ferromagnetism for the planar system.

No description available.

No description available.

No description available.

No description available.

No description available.

No description available.