Magnetic silica aerogels

Magnetic silica aerogels generated from both pure ferric nitrate and its mixture with an iron complex exhibit low saturation magnetization values of 14 and 8.5 emu g , respectively [6], in comparison with bulk maghemite values of 74-76 emu g . The low magnetization values suggest lack of crystal order. These materials may still be useful in catalysis and other applications. 

A further enhancement is provided by alternative detection methods. Pines and co-workers " " have coupled the use of HP xenon with a SQUID, which provides very high-sensitivity detection of magnetic fluxes at low resonance frequencies. The authors showed that the use of optically pumped xenon and a high-Tc SQUID device could be coupled to allow the detection of laser-polarized xenon gas at only 27 kHz, corresponding to a magnetic field of 2.3 mT. MRI of xenon adsorbed on a piece of silica aerogel was also shown using this approach (see Fig. 27). " SQUID... 

Casas LI, Roig A, Rodriguez E, MoUns E, Tejada J, Sort J (2001) Silica aerogel-iron oxide nanocomposites structural and magnetic properties. J Non-Cryst Solids 285 37-43... 

Carta D, Casula MF, Corrias A, Falqui A, Loche D, Mountjoy G, Wang P (2009) Structural and Magnetic Characterization of Co and Ni Silicate Hydroxides in Bulk and in Nanostructures within Silica Aerogels. Chem... 

Figure 4-12. Silica aerogel application as a Cherenkov counter installed in AMS (Alpha magnetic spectrometer).

Pore structure and sorption properties of silica aerogels studied by magnetic resonance imaging and pulsed-field gradient spectroscopy. Appl. Spectrosc.,... 

Fig. 7.18. Derived momentum distributions for the perturbed m = 0 state of ortho-positronium, for various gases (Nagashima et al., 1995) in an applied static magnetic field of 0.29 T. Reprinted from Physical Review A52, Nagashima et al., Thermalization of free positronium atoms by collisions with silica-powder grains, aerogel grains and gas molecules, 258-265, copyright 1995 by the American Physical Society.

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