M. F. H. Schuurmans

Magnetocrystalline anisotropy of RECo5 compounds

Abstract The magnetocrystalline anisotropy energy and anisotropy of the orbital angular momentum have been calculated ab initio for YCo 5 using the LMTO method. Quantitative agreement with experiment is found if a recently proposed orbital polarization correction is included. The anisotropy of the orbital angular momentum and the energy are strongly correlated. The crystal field parameters at the RE site in RECo 5 compounds, calculated using the FLAPW method, have the correct sign and are comparable to the experimentally observed values.

Exact and moment equation modeling of electron transport in submicron structures

We compare I‐Vcharacteristics of a semiconducting submicron n + nn + diode as predicted by extended moment equation approximations to those obtained from the solution of the corresponding Boltzmann equation. All lower order models fail in the predominantly ballistic regime. Moreover, the conductance is inadequately predicted by these models, even in nonballistic cases due to the high build‐in electric fields.

First-Principles Calculation of the Magnetocrystalline Anisotropy Energy of ConPdm Multilayers

The magnetocrystalline anisotropy energies of [001] and [111] oriented ConPdm multilayers (with n+m≤6) have been calculated from first principles using the linear muffin-tin orbital method in the atomic-spheres approximation together with the local-spin-density approximation. While the easy axes of all [111] ConPdm multilayers considered are found to be perpendicular to the film plane, [001] ConPdm multilayers are only found to be perpendicularly magnetized if they contain cobalt as monolayers. The magnetocrystalline anisotropy energy is calculated to be largest for [111] Co1Pd2 and decreases with increasing Co thickness. These predictions are in agreement with experiment.

Monte Carlo simulation of hot electrons in silicon p-i-n cold cathodes

Monte Carlo simulation of electron transport in p‐i‐n cold cathodes yields an exponential dependence of the efficiency on the work function similar to the relation found in the experiment. The effective temperature characterizing the exponential dependence is higher in the model than in the experiment and is not equal to the calculated electron temperature. The efficiency at breakdown decreases with the intrinsic layer width and is very sensitive to the X‐X intervalley scattering rates.

Superconducting proximity effect in thin-film Y1Ba2Cu3O7-delta-Ag/Al-Pb structures

We have studied the superconducting critical current 1. of Y1Ba2Cu3O7,-Ag/M-Pb proximity junctions. The current-voltage (I.V) characteristics are typically those of a superconductor-normal metal-superconductor (S-N-S) junction. The Y1Ba2Cu3O7.-Ag/Al-Pb junctions show sharp Shapiro steps in a microwave field. The dependence of step height on microwave power is well described by the Resistively Shunted Junction (RSJ) model, assuming a IC cx: Sin ( Josephson behaviour, where ço is the pha difference of the superconducting order parameter across the junction. The Josephson current shows an interference pattern in a magnetic field applied parallel to the junction plane.