Sample Length Dependence of Magnetic Moment Detected by a SQUID Magnetometer Using Nickel Cylinders

We report here on sample length dependence measurements in a second-order gradiometer superconducting quantum interference device (SQUID) magnetometer of pure nickel (Ni) cylinders, having a diameter of 1 mm and a length of 1-7 mm. The measured magnetic moment per unit mass significantly decreases with the sample length of the Ni cylinder, when a magnetic field of 7 T was applied parallel to the long axis of the cylinder. As an example, the magnetic moment per unit mass for the 5 mm Ni cylinder is between 97% and 94% of that for the 1 mm Ni cylinder, the number depending on the specific type of magnetometer used. The magnitude of decrease also depends on the length of the second-order gradiometer superconducting coil which differs with different models of SQUID magnetometers.

Automated summary

The study reported measurements in a second-order gradiometer superconducting quantum interference device (SQUID) magnetometer of pure nickel (Ni) cylinders. It found that the magnetic moment per unit mass of the Ni cylinder decreases with sample length, with the extent of decrease depending on the type of magnetometer used and the length of the second-order gradiometer superconducting coil.