Magnetizing a fabric with out making use of an exterior magnetic discipline is proposed by researchers at São Paulo State College (UNESP), Brazil, in an article printed within the journal Scientific Studies, the place they element the experimental strategy used to realize this aim.
The research was a part of the Ph.D. analysis pursued by Lucas Squillante underneath the supervision of Mariano de Souza, a professor at UNESP’s Division of Physics in Rio Claro. Contributions have been additionally made by Isys Mello, one other Ph.D. candidate supervised by Souza, and Antonio Seridonio, a professor at UNESP’s Division of Physics and Chemistry in Ilha Solteira. The group was supported by FAPESP.
“Very briefly put, magnetization happens when a salt is compressed adiabatically, with out exchanging warmth with the external environment,” Souza instructed. “Compression raises the temperature of the salt and on the identical time rearranges its particles’ spins. Because of this, the entire entropy of the system stays fixed and the system stays magnetized on the finish of the method.”
To assist perceive the phenomenon, it’s price recalling the fundamentals of spin and entropy.
Spin is a quantum property that makes elementary particles (quarks, electrons, photons, and so on.), compound particles (protons, neutrons, mesons, and so on.) and even atoms and molecules behave like tiny magnets, pointing north or south—up spin and down spin—when submitted to a magnetic field.
“Paramagnetic supplies like aluminum, which is a steel, are magnetized solely when an external magnetic field is utilized. Ferromagnetic supplies, together with iron, could show finite magnetization even within the absence of an utilized magnetic discipline as a result of they’ve magnetic domains,” Souza defined.
Entropy is principally a measure of accessible configurations or states of the system. The better the variety of accessible states, the better the entropy. Austrian physicist Ludwig Boltzmann (1844-1906), utilizing a statistical strategy, related the entropy of a system, which is a macroscopic magnitude, with the variety of attainable microscopic configurations that represent its macrostate. “In the case of a paramagnetic material, entropy embodies a distribution of probabilities that describes the number of up spins or down spins in the particles it contains,” Souza mentioned.
Within the just lately printed research, a paramagnetic salt was compressed in a single path. “Application of uniaxial stress reduces the volume of the salt. Because the process is conducted without any exchange of heat with the environment, compression produces an adiabatic rise in the temperature of the material. A rise in temperature means a rise in entropy. To keep total entropy in the system constant, there must be a component of local reduction in entropy that offsets the rise in temperature. As a result, the spins tend to align, leading to magnetization of the system,” Souza mentioned.
The whole entropy of the system stays fixed, and adiabatic compression leads to magnetization. “Experimentally, adiabatic compression is achieved when the sample is compressed for less time than is required for thermal relaxation—the typical time taken by the system to exchange heat with the environment,” Souza mentioned.
The researchers additionally suggest that the adiabatic rise in temperature may very well be used to analyze different interacting techniques, corresponding to Bose-Einstein condensates in magnetic insulators, and dipolar spin-ice techniques.
Lucas Squillante et al, Elastocaloric-effect-induced adiabatic magnetization in paramagnetic salts because of the mutual interactions, Scientific Studies (2021). DOI: 10.1038/s41598-021-88778-4
Researchers suggest a technique of magnetizing a fabric with out making use of an exterior magnetic discipline (2021, July 29)
retrieved 29 July 2021
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