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While searching for a “new age” cryogenic insulating material for use in magnetic fields, the silica aerogel known as Cryogel^®x201 was identified for its performance at low temperatures [1]. The thermal conductivity of Cryogel^® has been reported [2], but the magnetic properties have not been characterized to date. Applications in high magnetic field instrumentation establish a necessity to fingerprint the magnetic properties of Cryogel^®. Using a commercial magnetometer, magnetization data, M(2 K ≤ T ≤ 300 K, B = 100 mT) and M(T = 2 K, −1 T ≤ B ≤ 7 T), were collected. These data sets were fit to a Brillouin function with a Curie-like background contribution to extract parameters, namely the spin value and the concentration of magnetic entities. Ultimately, this unexpected magnetic signal is conjectured to be associated with Fe₂O₃ nanoparticles.

[1] https://www.pacorinc.com/wp-content/uploads/Cryogel-x201-Datasheet.pdf

[2] V. Ilardi et al., IOP Conf. Ser.: Mater. Sci. Eng. 756 (2020) 012005, doi:10.1088/1757-899X/756/1/012005