Versatile Hall magnetometer with variable sensitivity assembly for characterization of the magnetic properties of nanoparticles

TL;DR

This paper presents a versatile, adjustable-sensitivity Hall magnetometer capable of rapidly measuring magnetic properties of nanoparticles, bulk materials, and liquids, with accuracy comparable to commercial devices and applications in nanoparticle characterization.

Contribution

The paper introduces a novel, adjustable-sensitivity Hall magnetometer that can quickly measure magnetic properties of various samples, including nanoparticles, with high accuracy and versatility.

Findings

Achieves a magnetic moment sensitivity of 1.3×10⁻⁹ Am².

Can measure complete magnetization curves in minutes.

Provides nanoparticle size estimates consistent with other techniques.

Abstract

A Hall magnetometer with variable sensitivity is constructed to measure the magnetic properties of magnetic nanoparticles manufactured by different methods. This novel magnetometer can also be used to measure bulk materials and samples in liquids. The magnetometer is constructed with two commercial Hall-effect sensors in an acrylic structure, which serves as the support for a micrometer and the circuit board with the sensors. For operation, the magnetometer it acquires a complete magnetization curve in a few minutes. If has a magnetic moment sensitivity of 1.3*10-9 Am2 to sensitivity of 493 mV/mT, the sensitivity can be adjustable in the range of 10 to 493 mV/mT. Its performance is tested with magnetic nanoparticles. As an application example, we estimate the mean diameter of the nanoparticles using the magnetic curves. The results are compared with those obtained by other techniques, such as transmission electron microscopy (TEM), X-ray diffraction (XRD) and dynamic light scattering (DLS). The magnetization results are also compared with those obtained by independent commercial magnetometers, which reveals errors of approximately 0.31 Am2/kg (i.e., 0.6%) in the saturation region.