The use of magnetic fields in semiconductor crystal growth

Series, R.W.; Hurle, D.T.J.

doi:10.1016/0022-0248(91)90036-5

Cited by 189 publications

(80 citation statements)

References 64 publications

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“…An alternative method is to damp the convection by growing the crystals in the presence of a magnetic field (Garandet & Alboussière 1999;Series & Hurle 1991). The convective motion of the electrically conducting melt in a magnetic field generates electrical currents, which interact with the magnetic field resulting in a damping force on the flow.…”

Section: Introductionmentioning

confidence: 99%

Magnetohydrodynamic damping of convective flows in molten gallium

Hof

Juel²,

Mullin

2003

J. Fluid Mech.

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We report the results of an experimental study of magnetohydrodynamic damping of sidewall convection in a rectangular enclosure filled with gallium. In particular we investigate the suppression of convection when a steady magnetic field is applied separately in each of the three principal directions of the flow. The strongest damping of the steady flow is found for a vertical magnetic field, which is in agreement with theory. However, we observe that the application of a field transverse to the flow provides greater damping than a longitudinal one, which seems to contradict available theory. We provide a possible resolution of this apparent dichotomy in terms of the length scale of the experiment.

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Section: Introductionmentioning

confidence: 99%

Magnetohydrodynamic damping of convective flows in molten gallium

Hof

Juel²,

Mullin

2003

J. Fluid Mech.

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“…One method of controlling the convection is to apply an external magnetic field as reviewed by Series & Hurle (1991). This induces an electromotive field which can be non-uniform in regions in the melt.…”

Section: Introductionmentioning

confidence: 99%

Magnetohydrodynamic convection in molten gallium

et al. 1999

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We present the results of an experimental and numerical study of the effects of a steady magnetic field on sidewall convection in molten gallium. The magnetic field is applied in a direction which is orthogonal to the main flow which reduces the convection and good agreement is found for the scaling of this effect with the relevant parameters. Moreover, qualitatively similar changes in the structure of the bulk of the flow are observed in the experiment and the numerical simulations. In particular, the flow is restricted to two dimensions by the magnetic field, but it remains different to that found in two-dimensional free convection calculations. We also show that oscillations found at even greater temperature gradients can be suppressed by the magnetic field.

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“…By changing the strength and orientation of the imposed magnetic field, additional possibilities for affecting flow and heat transfer can be investigated. Possible areas of application where magnetic fields can be used to control flow and heat transfer include control of the growth rate and microstructure of materials [2] or protein crystals [3]. Starting from the pioneering work of Braithwaite et al [4], the potential for magnetically controlled convection in paramagnetic, or even in ordinary (mainly diamagnetic), fluids (water) has been investigated both experimentally and numerically, e.g., [5][6][7][8][9][10][11][12].…”

mentioning

confidence: 99%

Oscillatory states in thermal convection of a paramagnetic fluid in a cubical enclosure subjected to a magnetic field gradient

et al. 2012

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We report experimental and numerical studies of combined natural and magnetic convection of a paramagnetic fluid inside a cubical enclosure heated from below and cooled from above and subjected to a magnetic field gradient. Values of the magnetic field gradient are in the range 9 |grad|b 0 | 2 | 900 T 2 /m for imposed magnetic field strengths in the center of the superconducting magnet bore of 1 |b 0 | max 10 T. Very good agreement between experiments and simulation is obtained in predicting the integral heat transfer over the entire range of working parameters (i.e., thermal Rayleigh number 1. Natural convection for heated-from-below configurations serves as a paradigm for a wide range of environmental, astrophysical, and industrial applications [1]. An interesting case of thermal convection is when the working fluid becomes magnetized in the presence of an external magnetic field. In such a case, in addition to gravity, the magnetization force is also important. By changing the strength and orientation of the imposed magnetic field, additional possibilities for affecting flow and heat transfer can be investigated. Possible areas of application where magnetic fields can be used to control flow and heat transfer include control of the growth rate and microstructure of materials [2] or protein crystals [3]. Starting from the pioneering work of Braithwaite et al. [4], the potential for magnetically controlled convection in paramagnetic, or even in ordinary (mainly diamagnetic), fluids (water) has been investigated both experimentally and numerically, e.g., [5][6][7][8][9][10][11][12]. A major contribution of these studies was in providing the integral heat transfer (Nusselt number) behavior under strong magnetic field gradients and in reporting some basic flow visualisations. All these studies addressed steady laminar flow regimes. The goal of our present investigation is to extend the range of working parameters toward transitional or potentially turbulent flow regimes. This is achieved, first, by employing significantly larger magnetic field gradients generated by state-of-the-art superconducting helium-free magnets (up to 900 T 2 /m for magnetic field strength of 10 T, in contrast to up to 200 T 2 /m for magnetic field strength of 5 T in previous studies); second, by using fluids with lower Prandtl numbers; and, finally, by performing a series of three-dimensional time-dependent simulations that revealed detailed insights into the dynamics and spatial reorganization of flow and thermal structures. Strong magnetic field gradients are generated by the superconducting helium-free magnet shown in Fig. 1. The calculated distributions of the magnetic field and resulting gradients for the upper limit of working conditions are shown in Fig. 2. The cubical enclosure can be positioned at different locations along the vertical axis of the superconducting magnet and combined effects (subtractive or additive) of the gravitational and magnetization forces can be generated. The suppression of the flow and heat transfer can be...

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The use of magnetic fields in semiconductor crystal growth

Cited by 189 publications

References 64 publications

Magnetohydrodynamic damping of convective flows in molten gallium

Magnetohydrodynamic damping of convective flows in molten gallium

Magnetohydrodynamic convection in molten gallium

Oscillatory states in thermal convection of a paramagnetic fluid in a cubical enclosure subjected to a magnetic field gradient

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