ON THE CALIBRATION OF VIBRATING SAMPLE MAGNETOMETERS WITH THE HELP OFNICKEL REFERENCE SAMPLES

Nickel reference samples are often used to calibrate magnetometers, bu t the data available on temperature and field dependence of the magnet ization differ considerably. We investigated the temperature dependenc e and the influence of the sample shape on the field dependence of the magnetization of nickel samples with a vibrating sample magnetometer. Three different Ni materials had a temperature coefficient of 5 . 10( -4)/K. The field dependence can be described by a sum of a term propor tional to the field H and a second one proportional to H-2. The relati ve deviations between experimental and fitted magnetization values in the field range 0.5 T less-than-or-equal-to mu0H less-than-or-equal-to 8 T are less than 10(-3) and show no systematic change with the field . Only the nonlinear term shows a strong dependence on the sample shap e and is important for fields mu0H less-than-or-equal-to 2 T.