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Magnetic Nanomaterials and Their Relevance in Transesterification Reactions
Published in Bhaskar Singh, Ramesh Oraon, Advanced Nanocatalysts for Biodiesel Production, 2023
António B. Mapossa, Michael Daramola
The vibrating sample magnetometer (VSM) is a widely used technique to investigate the magnetic properties of magnetic nanoparticles (MNPs) as a function of an applied external magnetic field usually between –3 and 3 Tesla. Like most conventional magnetization probes, the technique is not element specific, but it rather measures the whole magnetization (Faraji, Yamini, & Rezaee, 2010). Based on the obtained VSM curve at low and room temperatures, the magnetic behaviour of the MNPs as well as information of the magnetic parameters such as saturation magnetization (Ms), remnant magnetization (Mr) and coercive field (Hc) can be determined (Mapossa, Dantas, Diniz, Silva, Kiminami, & Costa, 2017; Dantas, Leal, Mapossa, Silva, & Costa, 2016). Ferromagnetic properties can be acceptable after supporting the active sites, such that the catalyst can be separated from the reaction system quickly and efficiently (Wang, Sudarsanam, Xu, Zhang, Li, & Yang, 2020). A study carried out by Yan et al. (2007) employed the VSM technique to evaluate the magnetic property of magnetic nanoparticles (Fe3O4). Therefore, the superparamagnetic behaviour of nanoparticles was observed (Figure 6.8).
Characterization of HTS Powders and Components
Published in A. G. Mamalis, D. E. Manolakos, A. Szalay, G. Pantazopoulos, Processing of High-Temperature Superconductors at High Strain Rates, 2019
A. G. Mamalis, D. E. Manolakos, A. Szalay, G. Pantazopoulos
The most commonly dc-magnetometers, such as VSM (vibrating sample magnetometer) and SQUID, measure the magnetic moment of the sample. If the sample to be measured does not have a permanent magnetic moment, an applied field is required to magnetize it. A detection coil is then used to detect the change in magnetic flux, due to the presence of the magnetic moment. The sample flux, coupled to the detection coil, is made to vary by the sample movement. In a VSM system, the sample is vibrated near the detection coil; as the sample vibrates, an ac-signal is generated at a frequency determined by the sample oscillation. In a SQUID system, the sample only passes through the detection coil. The dc-magnetic susceptibility, χdc is given by the equation () χdc=MHdc
Multiferroic Polymer Film Composites for Memory Application
Published in Alexander V. Vakhrushev, Omari V. Mukbaniani, Heru Susanto, Chemical Technology and Informatics in Chemistry with Applications, 2019
Rehana P. Ummer, Nandakumar Kalarikkal
Initially, (1-x) BiFeO3-xNaNbO3 ceramic powder for x = 0, 0.05, 0.1, and 0.5 were prepared by Pechini method.34 PMMA–BiFeO3–NaNbO3 films were prepared by solvent casting method. PMMA solution is prepared by using acetone as the solvent. The ceramic nanoparticles (5 wt.%) were then dispersed in PMMA solution and then ultrasonicated for 30 min. A gelatinous brownish white solution was obtained. The obtained solution is poured into Petri dishes and kept at room temperature for 2–3 days. Within this time the desired films were formed. The crystal structures of the samples were examined by Phillips X’Pert PANalytical X-ray diffraction (XRD) with Cu-Ka radiation (1.54056 Å). Step scanned powder XRD data were collected in the 2θ range 10–80° at room temperature. The detailed structural analysis was performed using scanning electron microscope (SEM) (JEOL JSM 6390), and confocal Raman spectroscopy. A conventional ME measurement has been carried out using the lock-in amplifier method and room temperature dielectric studies were performed using an Agilent E4980A precision LCR meter. The magnetization measurements were performed using vibrating sample magnetometer (VSM).
Experimental and theoretical assessment of Fe-doped indium-oxide-based dilute magnetic semiconductors
Published in Philosophical Magazine, 2019
Rana Mukherji, Vishal Mathur, Arvind Samariya, Manishita Mukherji
The above studies signify that the dopants and sintering methods play major roles in the origin of FM properties in In2O3- based DMSs as both are associted with oxygen vacancies. The present study concerns an experimental and theoretical characterisation of Fe-doped In2O3 specimens. The specimens are structurally characterised through X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. Magnetic properties are determined through a vibrating sample magnetometer (VSM). The study also investigates the impact of air and H2 sintering on the magnetic properties. A theoretical analysis of the magnetic properties has been made based on a bound magnetic polaron (BMP) model. A hierarchical cluster analysis (HCA) has also been performed to strengthen the experimental findings. MATLAB-based simulations have been executed on SEM micrographs to confirm the homogeneity in the particle distribution of the specimens.
Deposition of iron oxide nanoparticles on glass mat using DC magnetron sputtering method-magnetic properties
Published in The Journal of The Textile Institute, 2022
Sheila Shahidi, Maryam Yazdizadeh, Zahra Motaghi, Seyed Mohammad Elahi, Rattanaphol Mongkholrattanasit
Therefore, according to the results, it can be said that the thickness of the iron layer increases with increasing sputtering time. Magnetic properties can be measured by a vibrating sample magnetometer (VSM). VSM measurements were also applied to examine the influence of Fe sputtering on the magnetic properties of fabrics. Changes in the maximum magnetization and the hysteresis loop coercive depend on the amount of Fe substitution (Lee et al., 2019). According to Figure 12, the sputtered sample in 4 h-sample 3, which was thicker, showed the magnetic property.