Magnetic Susceptibility Measurement System for Small and Weak Magnetic Substances.

摘要

In this study a system is constructed which uses a force method for taking magnetic susceptibility measurements of small (< 100 mg) and weak (< 100× 10-6 emu/g) magnetic substances. The system is constructed with several pieces of readily available hardware. Some of the hardware includes a stable frame structure, a CAHN electrobalance, electromagnet, a thermocouple, a power supply, interfaces, and a personal computer. Each of these components is tested individually as well as together with other devices. Since the electrobalance is extremely sensitive the balance must be placed on a stable frame. The completed system is capable of studying the magnetic properties from room temperature to 77 K of a variety of samples. In addition, a novel method is developed to produce hysteresis loops for especially small and weak magnetic samples.;Extensive testing is done to ensure the magnetization results obtained on known samples compare with what has been reported. Some of the samples that have been measured are MnO (TN was 122 K), CdSe (magnetic susceptibility was -0.3 × 10-6 emu/g) with iron attached ligands, FexTeyOz type samples with and without nickel, a YBaCuO superconductor, and cells doped with magnetite nanoparticles. The results are compared to measurements made with SQUID magnetometers.