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In this paper, thermal magnetization rotation of small Co nanoparticles was investigated. We test the performance and validity of a semi-implicit time integration scheme.

Minimum energy paths and energy barriers are calculated for the free data layer in elliptical magnetic random access memory elements using a recently developed method that combines the nudged elastic band method with finite-element micro-magnetics. The method calculates the magnetic states along the most probable reversal paths for applied fields below the zero temperature switching field. The reversal mode in the minimum energy path depends on the strength of the external field. With increasing easy axis field, the reversal mode becomes more inhomogeneous than at lower fields.

In this work, we numerically investigate the effect of intergranular exchange, media texture, easy axes distribution, and the field profile on the switching speed.

Summary form only given. Discrete media show great potential for future ultra-high density magnetic recording. A possible patterning scheme is the removal of magnetic material from existing media using a focused ion beam. Patterning significantly changes the hysteresis properties. In this work we apply a hybrid finite element/boundary element method to simulate the magnetization reversal process in a perpendicular granular film, a patterned media, and a single magnetic island. We start with a continuous CoCrPt film consisting of 625 columnar grains which are obtained from a Voronoi tesselation. The grain diameter is 10 nm and the film thickness is 21 nm. In a second step, we take out elements in a grid pattern, to obtain an array of individual islands. The island size is 70 nm with a gap of 20 nm. The subsequent calculation of equilibrium states solving the Gilbert equation of motion provides the demagnetization curve.

Recent developments and advances in high speed silicon germanium heterojunction bipolar transistor (Si/SiGe HBT) research are reviewed. Special emphasis is laid on the Si/SiGe HBT activities in Germany. The paper describes the basic design of the Si/SiGe HBT and its advantages over conventional Si BJTs. A survey on the high frequency properties of Si/SiGe HBTs is given, outstanding experimental results are highlighted, and possible applications of these transistors are discussed. Recent results from the authors laboratory concerning the simulation and design of Si/SiGe HBTs are presented.

This paper deals with the temperature behavior of Si/SiGe/Si-HBT. Experimental data are compared with results of numerical simulations. DC and RF results are explained by analytical formulas. It was found that the temperature behavior of Si/SiGe/Si HBT are similar to that of all silicon devices.

The aim of this work is to compare device simulation results for a Si/SiGe/Si-hetero bipolar transistor (HBT) by using Monte Carlo (MC), energy transport (ETM), and drift-diffusion (DDM) models. Numerical results of velocity overshoot, potential, and carrier density are compared before and after the onset of the Kirk effect. This is to our knowledge the first time of such a comprehensive comparison of the three models for Si/SiGe/Si HBTs. The influence of velocity overshoot and spurious overshoot on the DC and RF behaviour are discussed.

This paper reports the differences in 2D device-level simulation based on drift-diffusion-ac and hydrodynamic-ac analysis of SiGe-HBTs. Different Ge profiles were simulated to determine the influence of nonstationary transport effects on device performance. A comparison between the two models is useful in order to estimate the differences of both models in device structure optimizing processes.