A SAMPLE HOLDER DESIGN AND CALIBRATION TECHNIQUE FOR THE QUANTUM DESIGN MAGNETIC-PROPERTIES MEASUREMENT SYSTEM SUPERCONDUCTING QUANTUM INTERFERENCE DEVICE MAGNETOMETER

Magnetic measurements performed on low-susceptibility materials often generate concern for the contribution of the sample holder's moment to the resultant measurement value. In this article, we present a unique design of a sample holder and accompanying calibration technique used to obtain accurate magnetic-moment values from compact, low-susceptib ility samples measured with the quantum design magnetic properties mea surement system superconducting quantum interference device (SQUID) ma gnetometer. The sample holder design is simple, highly symmetric, easi ly fabricated, useful over the full temperature range of the magnetome ter and is amenable to a correction algorithm that allows the experime ntalist to determine accurately the contribution of the sample holder to the measured value. The sample holder is modeled as a semi-infinite linear density of dipoles, and the response of the internal SQUID coi l sections to these dipoles is summed to represent the system response to the sample holder. When the correction algorithm was applied to a measurement of NIST SRM 763 aluminum mounted in the sample holder, the error in the magnetic susceptibility decreases substantially from 41. 9% down to 1.1%. (C) 1996 American Institute of Physics.