The Effect of an External Magnetic Field on the Impurity Distribution in an RF-FZ Silicon Crystal During the Growth Process

2000 ◽  
Author(s):  
Tetsuo Munakata ◽  
Satoshi Someya ◽  
Ichiro Tanasawa

Abstract The impurity concentration distribution in a silicon crystal during the floating zone (FZ) growth process under radio-frequency (RF) heating and the effect of an externally applied magnetic field on the impurity distribution in the crystal have been investigated numerically. The main purpose of the study is to clarify the characteristics of the impurity distribution in the silicon crystal under the RF-FZ crystal growth process, and the effect of an externally applied magnetic field on such an impurity distribution. The numerically obtained characteristics on impurity distribution in the crystal are as follows. In the case of excluding the external magnetic field, impurity concentration in the crystal varies due to the fluctuation of the melt flow. If we apply an external magnetic field, such impurity variation in the crystal disappears due to the stabilizing effect of the external magnetic field. Further, the crystal growth rate is decreased, the impurity concentration in the crystal is also decreased. The impurity segregation coefficient does not affect the impurity distribution in the crystal.

2002 ◽  
Author(s):  
Masayuki Aoshima ◽  
Akira Satoh ◽  
Geoff N. Coverdale ◽  
Roy W. Chantrell

A ferrofluid is a suspension of ferromagnetic spherical particles in a base liquid (1), and is well known as a functional fluid which responds to an external magnetic field to give a large increase in the viscosity. Such a significant increase in the viscosity is due to the fact that chain-like clusters are formed owing to magnetostatic interactions between particles in an applied magnetic field. The microstructure formation offers a large resistance to a flow field that gives rise to a significant increase of the apparent viscosity (2).


2000 ◽  
Vol 14 (25n27) ◽  
pp. 3032-3037 ◽  
Author(s):  
M. CIRILLO ◽  
V. MERLO ◽  
R. RUSSO ◽  
P. CIKMACS

We report on measurements on very long, L ≃ 30λj, NbAlOxNb underdamped in-line junctions, on which we observed displaced linear slope (DLS) generated by the application of an external magnetic field. We study the behaviour of the branches as a function of the applied magnetic field in terms of both current amplitude and voltage position. The DLS is seen to shift rigidly towards higher voltages when increasing the field, spanning a region roughly centred around the Josephson plasma frequency. We discuss the behaviour of linear branches in terms of one dimensional flux-flow along the extended side of the junction, comparing our data with the results of numerical modeling; from these calculations the non-resonant nature of DLS is very evident, in contrast to the resonant regime giving rise to Fiske steps (FS).


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