Detection of magnetic moment in thin films with a home-made vibrating sample magnetometer

Abstract

This paper explores the optimization of an array of pick-up coils in a home-made vibrating sample magnetometer for the detection of magnetic moment in thin films. Sensitivity function of a 4-coils Mallinson configuration was numerically studied for the determination of the physical dimensions that enhance the sensitivity of the magnetometer. By performing numerical simulations using the Biot-Savart law combined with the principle of reciprocity we were able to determine the maximum values of sensitivity and the influence of the separation of the coils on the sensitivity function. After the optimization of the pick-up coils, the vibrating sample magnetometer was able to detect the magnetic moment of a 100 nm-thickness Fe 19 Ni 81 magnetic thin film along and perpendicular to the in-plane anisotropy easy axis. The implemented vibrating sample magnetometer is able to detect changes in the magnetic moment of ∼ 2 × 10 −4 emu.

Development of a New Electrochemical Sensor Based on Mag-MIP Selective Toward Amoxicillin in Different Samples

“…Magnetic properties were analyzed by measurements of vibrating sample magnetometry (VSM). The equipment was built for research (Jordán et al, 2018 ). It shows a hysteresis plot for a magnetic field up to 2,500 Oe with a resolution of ~2 × 10 −4 emu.…”

Magnetic Materials and Systems: Domain Structure Visualization and Other Characterization Techniques for the Application in the Materials Science and Biomedicine

“…On the basis of the "Modern Theory of Magnetism", the appearance of strong magnetic phenomena in materials and molecular structures is due to the presence of chemical elements with a particular electronic configuration, namely: Iron (Fe), nickel (Ni), cobalt (Co), manganese (Mn), chromium (Cr), and some rare earth metals [37]. Independently from the types of magnetism, the most common method for evaluating the magnetic response in materials is the determination of the magnetization (hysteresis) curves by means of a magnetometer [38]. Even if there are several configurations of magnetometers, the most common one is the vibrating sample mode (VSM).…”

“…In presence of an external magnetic field, nanoparticles align following the magnetic field direction as for paramagnetic materials. However, due to their ferro/ferri-magnetic origin, such nanomaterials show very high magnetic susceptibility (larger than common paramagnetic materials, i.e., "super"paramagnetism) and absence of hysteresis (H ci -values close to zero, and M r -values very low) [38].…”

“…In presence of an external magnetic field, nanoparticles align following the magnetic field direction as for paramagnetic materials. However, due to their ferro/ferri-magnetic origin, such nanomaterials show very high magnetic susceptibility (larger than common paramagnetic materials, i.e., "super"paramagnetism) and absence of hysteresis (Hci-values close to zero, and Mr-values very low) [38]. Conversely to paramagnetism, diamagnetism is the capability of repel/oppose to an applied external magnetic field, due to the absence of unpaired electrons, giving weak negative magnetization and susceptibility [56].…”

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“…The ferromagnetic behavior of Ni-Zn ferrite-epoxy composite thin films was revealed by VSM, and the degree of saturation magnetization of the composites increased with the addition of NiZn ferrite nanoparticles [20]. An optimized VSM design was determined using numerical calculations, based on the principle of reciprocity and the Biot-Savart law, and was able to detect the magnetic moment of a 100 nm-thick Fe 19 Ni 81 film and its change of ~ 2 × 10 −7 A m 2 [21]. However, VSMs of normal design are only applicable to samples with small dimensions, thin films, or other small electronic components.…”