A Simple Portable Magnetometer Based on Magnets and Hall-Effect Sensors Capable of Measuring Magnetic Properties

A magnetometer based on Hall effect sensors was developed using a 1020 steel base, two magnets (K&J Magnetics, Pipersville, PA, USA), and two Hall effect sensors: MLX-90215 (Melexis Inc., San Jose, CA, USA) and AD-AD22151 (Analog Devices, Inc., Wilmington, MA, USA). Both sensors were assembled on an acrylic support and powered with a 5-volt battery. The readings can be taken using bench multimeters (HP 34401A or Iminipa ET-2042D). The magnetometer records magnetic hysteresis loop and saturation by applying a field of up to 0.33 T at room temperature. The device was tested using magnetic hysteresis data from samples of 99% pure nickel sphere and magnetite microparticles. A dipole magnetic model was used to obtain the moment of the samples. The sensor used for reading the induced magnetic field of the sample AD-AD22151 has a sensitivity can be adjusted from to 110 mV/mT. This device is cheap, versatile, and easy to build, and despite its low accuracy, when compared to commercial equipment, it can be useful in low-budget teaching and research laboratories.