Silicon magnetic susceptibility

Exists in two adotropic modifications. Crystalline sihcon is made up of grayish-black lustrous needle-hke crystals or octahedral platelets cubic structure Amorphous sdicon is a brown powder. Other physical properties are density 2.33g/cm3 at 25°C melts at 1,414°C high purity liquid silicon has density 2.533 g/cm at its melting point vaporizes at 3,265°C vapor pressure 0.76 torr at 2,067°C Mohs hardness 6.5. Brinell hardness 250 poor conductor of electricity dielectiric constant 13 critical temperature 4°C calculated critical pressure 530 atm magnetic susceptibility (containing 0.085%Fe) 0.13x10 insoluble in water dissolves in hydrofluoric acid or a mixture of hydrofluoric and nitric acids soluble in molten alkalies. 

This may be equated to the experimental estimate of this term (Hudgens, Kastner, and Fritzsche, 1974, and Hudgens, 1973) for silicon, to give a value y , = 1.12. Following Chadi, White, and Harrison (1975), let us use this same value for all materials in estimating the susceptibility. Notice that the order of magnitude of magnetic susceptibility is e jd divided by mc. Thus, in contrast to the dielectric susceptibility (which is of order unity), it is very small. 

X-ray diffraction (XRD) and magnetic susceptibility measurements were carried out on polycrystalline materials that had been calcined in oxygen. XRD powder patterns were recorded with Cu Ka radiation using a Ni filter on a Rigaku diffractometer. For reference all patterns were recorded with an internal NBS Si standard. After correcting the peak position based on the observed silicon line positions, the lattice constants were then refined by a least squares method weighted proportional to the square root of the height and inversely with the square of the width of the peak. 

Schenck JF (1996) The role of magnetic susceptibility in magnetic resonance imaging MRI magnetic compatibility of the first and second kinds. Med Phys 23 815 Sonder E, Stevens DK (1958) Magnetic properties of n-type silicon. Phys Rev 110 1027 Wehrspohn RB, Deane SC, French ID, Gale I, Hewett J, Powell MJ, Robertson J (2000) Relative importance of the Si-Si bond and Si-H bond for the stability of amorphous silicon thin film transistors. J Appl Phys 87 144... 

Silicon. H- Si double resonance of ot-Si H deposited from SiH4 has shown the presence of trapped H2. NMR spectroscopy has been used to precisely measure the bulk magnetic susceptibility of a-Si H films. Polysilses-quioxanes containing SiH groups have been characterised by H and Si NMR spectroscopy. NagSi46 has been studied in detail by Na and Si NMR spectroscopy. ... 

Fig. 1 Comparison of the magnetization curves of bare n silicon (full line), as-etched porous silicon prepared from the same wafer (dotted line), and aged porous silicon offering a native oxide layer (dashed line). All three samples show a diamagnetic behavior, whereas the estimated susceptibility varies between —1.2 10 (Si), —7.5 10 (as-etched), and —2.6 10 (aged). The measurements have been performed at T = 4.2 K. The diamagnetic behavior of porous silicon decreases if the sample is oxidized (in contrast to hydrogen terminated) which might be caused by the occurrence of dangling bonds...

Blakemore JS (1985) Solid state physics, 2nd edn. Cambridge University Press, Cambridge Candea RM, Gee CM, Hudgens SJ, Kastner M (1977) Temperature dependence of the diamagnetic and dielectric susceptibility of silicon. Phys Rev B 16 2657 Cullity BD, Graham CD (2008) Introduction to magnetic materials. Wiley, Hoboken Helms CR, Poindexter EH (1994) The silicon-silicon dioxide system its microstructure and imperfections. Rep Prog Phys 57 791... 

The carrier liquid of the ferrofluid used in the experiment (APG S lOn, Ferrotec) was a synthetic ester oil which was immiscible in silicone oil. The viscosity rj, density /O, and surface tension a of the ferrofluid at 25 °C were 0.406 kg/ms, 1330 kg/s, and 32xlO N/m, respectively. The saturation magnetization and the initial susceptibility X of this ferrofluid were 44 mT and 1.6, respectively. Two silicone oils with different viscosities were used to investigate the effect of viscous friction [—Si(CH3)20—] , with a kinematic viscosity of V = 50 cSt, and [—C7H80Si—], with a kinematic viscosity of 100 cSt. Both oils had approximately the same surface tension of 2.03 x 10 N/m and a density of 960kg/m. In the experiments, the ferrofluid droplet was surrounded... 

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