A convenient standard for low-field susceptibility calibration

Finely ground mixtures of magnetic iron oxide and glass provide a convenient calibration standard of moderate accuracy (approximately 5%) for low-field (<0.5 kA/m) magnetic susceptibility measurements. The use of powders allows fabrication of standards of nearly any shape and size. For our mixtures, which range from 0.063 to 11.8% iron oxide by weight, the susceptibility values vary from 2.65 x 10(-7) to 5.77 x 10(-5) m3/kg, and are nearly linear with iron oxide concentration.