China
Africa
Explore chapters and articles related to this topic
Crystal Structures and Properties of Nanomagnetic Materials
Published in Ram K. Gupta, Sanjay R. Mishra, Tuan Anh Nguyen, Fundamentals of Low Dimensional Magnets, 2023
Mirza H. K. Rubel, M. Khalid Hossain
Ferromagnetism, a prominent fundamental property of magnetic materials, originates from the parallel spin alignment and magnetic moments of the constituent atoms of materials referred to as electromagnets or magnetization electrons. Ferromagnetic materials bear permanent dipolar magnetic moments that are spontaneously oriented in a big mob with parallel alignment without an external magnetic field. The ferromagnetic properties of materials under an external field are characterized in detail by a well-known hysteresis loop, where two, primal entities coercivity, and remanence, are importantly considered. Ferromagnetism is a physical property found naturally in iron and magnetite (Fe3O4), an oxide of iron, and is often referred to as an intrinsic ferromagnet. It was discovered about 2000 years ago when magnetism attributes of these materials were investigated [38]. Moreover, cobalt, nickel, manganese, gadolinium, Tb, Dy, numerous alloys and compounds, and several rare-earth elements belong to this group. Compared to other classes of materials, ferromagnets are easily and strongly magnetized at saturation levels. At present, ferromagnetic materials are broadly and sophisticatedly employed in various devices essential to our modern life – for example, electric motors and generators, transformers, telephones, loudspeakers, magnetic recording gadgets, floppy discs, cassette tapes, credit card magnetic stripes, etc.
Electrical Aspects
Published in Frank R. Spellman, The Science of Wind Power, 2022
Early magnetic studies classified magnetic materials merely as being magnetic and nonmagnetic—that is, based on the strong magnetic properties of iron. However, because weak magnetic materials can be important in some applications, present studies classify materials into one of the following three groups: paramagnetic, diamagnetic, and ferromagnetic. Paramagnetic materials: These include aluminum, platinum, manganese, and chromium—materials that become only slightly magnetized even though under the influence of a strong magnetic field. This slight magnetization is in the same direction as the magnetizing field. Relative permeability is slightly more than 1 (i.e., considered nonmagnetic materials).Diamagnetic materials: These include bismuth, antimony, copper, zinc, mercury, gold, and silver—materials that can also be slightly magnetized when under the influence of a very strong field. Relative permeability is less than 1 (i.e., considered nonmagnetic materials).Ferromagnetic materials: These include iron, steel, nickel, cobalt, and commercial alloys—materials that are the most important group for applications of electricity and electronics. Ferromagnetic materials are easy to magnetize and have high permeability, ranging from 50 to 3,000.
Petroleum Geophysical Survey
Published in Muhammad Abdul Quddus, Petroleum Science and Technology, 2021
Almost all the non-metal elements are diamagnetic, that is to say they do not respond to a magnetic field. The non-metal cannot be magnetized. Para-magnetic elements are called ‘metalloids’; they response to magnetic fields and are magnetized temporarily. As soon as the external magnetic field is withdrawn, the induced magnetic field vanishes. Examples of this class are aluminum (Al) and antimony (Sb) and their minerals. Ferromagnetic materials are those elements that are readily magnetized by an external magnetic field. They retain the induced magnetic field after withdrawal of the external field. Examples of ferro-magnetic materials are minerals containing iron (Fe), nickel (Ni) and cobalt (Co).
Analysis of nonlinear thermal radiation and entropy on combined convective ternary (SWCNT-MWCNT-Fe3O4) Eyring–Powell nanoliquid flow over a slender cylinder
Published in Numerical Heat Transfer, Part A: Applications, 2023
Prabhugouda M. Patil, Hadapad F. Shankar
The magnetic dipole dramatically affects the efficiency of energy transport and the thickness of thermal boundary layers in ferrite nanoparticles. Ferromagnetic materials generate a strong magnetic field. As an outcome, the most commonly used magnetic material is Fe3O4 nanoparticles, and water is the most widely used base liquid in the examination. The liquid that resulted was Ferroliquid, also known as the magnetic liquid. In greater detail, Ferroliquid were colloidal suspensions of small magnetic particles in a carrier liquid. Ferrofluids were used as catalysts in wastewater treatment and mechanical damping in loudspeakers and heat exchangers, among other biomedical and electronic equipment. Acharya et al. [23] have examined combined convection flow by considering carbon nanotube nanoparticles. Their outcome reveals that SWCNT nanoliquid has a higher energy transference regardless of the magnetic parameter than MWCNT nanoliquid. Muhammad et al. [24] investigated the combined convective motion of CNTs about a stretched cylinder. Nath and Murugesan [25] have analyzed the combined convective motion of the cylinder by considering Fe3O4-Cu-Al2O3 nanoparticles.
Production and characterization of magnetic textiles
Published in The Journal of The Textile Institute, 2022
Zeynep Omerogullari Basyigit, Ali Riza Beden, Hatice Coskun
In this study, 100% cotton fabrics with additional magnetic properties were processed into smart textiles. Ferromagnetic materials are used to impart magnetism to fabrics. This is because materials from the ferromagnetic group have magnetic moments without the need for an external magnetic effect to be applied to them. When an external magnetic field is applied, the arrangement of the magnetic moments of the atoms may change, but they do not lose their magnetic properties (Tekerek 2007; Altunay, 2010). In other words, a permanent magnetic field is generated (Kaya, 2017). These properties of the materials of the ferromagnetic group are very important for their applicability on textile surfaces and the sustainability of these properties. Therefore, the compound Fe3O4 from the ferromagnetic group was used in the study (Çölmekçi, 2016). Fe3O4 material, which has the highest magnetic property among all naturally occurring minerals on earth, has the advantage of being suitable for the parameters of production processes (fixing temperature, finishing processes, etc.) as it loses its magnetic property above 585 °C (Néel, 1952).
Multiphysics finite element model for the computation of the electro-mechanical dynamics of a hybrid reluctance actuator
Published in Mathematical and Computer Modelling of Dynamical Systems, 2020
F. Cigarini, E. Csencsics, J. Schlarp, S. Ito, G. Schitter
The electromagnetic material parameters of the steel have to be defined to compute the influence of the eddy currents and of the hysteresis on the electromagnetic dynamics. Eddy currents arise in conductive materials in response to an external variable electromagnetic field. The intensity of these currents is dependent on the electrical conductivity of the material [34]. Hysteresis is due to the cycle of magnetization and demagnetization of the ferromagnetic material as a result of the variable electromagnetic field. This is graphically represented by the hysteresis loop (shown in Figure 5 for EN 10025 S235JR), which is univocally defined by the intrinsic coercivity , the remanence and the magnetizing curve (dashed line in Figure 5). In order to compute the effect of hysteresis on the torque in the time domain, the magnetizing curve, as well as the values of , and need to be defined for EN 10025 S235JR [26,35] and are listed in Table 2.