Oscillatory biquadratic coupling in Fe/Cr/Fe(001)

Copyright © 1997 The American Physical SocietyPolar Kerr measurements have been used to measure the dependence of the biquadratic coupling strength B12 on Cr thickness in an Fe/Cr/Fe trilayer. The overall behavior, which consists of a maximum coupling strength at dCr=5 Å (3.5 ML) with a falloff at greater Cr thicknesses, is found to be consistent with in-plane Kerr and Brillouin light-scattering measurements performed on the same sample. The polar Kerr measurements suggest additionally that B12 increases from zero near zero Cr thickness, and that it oscillates in magnitude after the first peak, with a second peak in B12 occurring at about dCr=12 Å (8.3 ML). The positions and heights of the first and second biquadratic coupling maxima, in relation to the first bilinear coupling maximum, show excellent agreement with previous measurements by Köbler et al. of the biquadratic coupling behavior in Fe/Cr/Fe, and also show good agreement with the predictions of an intrinsic biquadratic coupling mechanism due to Edwards et al

A framework for cloud-aware development of bag-of-tasks scientific applications

The potential of cloud computing is still underutilised in the scientific computing field. Even if clouds probably are not fit for high-end HPC applications, they could be profitably used to bring the power of low-cost and scalable parallel computing to the masses. But this requires simple and friendly development environments, able to exploit cloud scalability and to provide fault tolerance. This paper presents a framework built on the top of a cloud-aware platform (mOSAIC) for the development of bag-of-tasks scientific applications. The architecture of the framework is thoroughly described, and the results of performance tests on a combinatorial optimisation application are discussed, evaluating the overhead introduced by the platform and by the cloud environment