Evaluation and Preparation of Ferromagnetic Liquid Composites for Use at Millimeter Wavelengths

摘要

Ferrofluid composites containing polystyrene, tin, copper, aluminium, carbon and silver particles 1 to 50 micron in diameter have been prepared by dispersing the articles in ferrofluids with M s = 400 to 800 G. Thin film samples 1 micron to 1 mm thick have been studied using a 3 mm microwave source and Fourier Transform Spectrometry. Large microwave absorptions (60%) which are induced by small fields of less than 100 Oe have been observed in thn film composites containing metal particles. Magnetic absorptions arise from chain formation in composition and this has been modelled using Monte-Carlo simulations. Good agreement between the observations and theoretical predictions is obtained. Keywords include: Magnetic Fluids; Composites; Thin films; Microwave; Dichroism; and Birefringence.