Magnetizing a material without applying an external magnetic field has been proposed in an article published in a journal by researchers at the State University of Sao Paulo (UNESP) in Brazil. Science report, Here we detail the experimental approach used to achieve this goal.
This study was part of a PhD. A study pursued by Lucas Squillante under the supervision of Marianode Souza, a professor of physics at UNESP in Rio Claro. I also contributed another PhD, Isys Mello. Candidates directed by Souza and Antonio Seridonio, a professor of physical chemistry at UNESP in Ilha Solteira. This group was supported by FAPESP.
“Simply put, magnetization occurs without heat exchange when the salt is adiabatically compressed. External environment “Compression raises the temperature of the salt and at the same time rearranges the spins of its particles. As a result, the sum entropy The system remains constant and the system remains magnetized at the end of the process. “
It is worth remembering the basics of spin and entropy to help us understand the phenomenon.
Spin is a quantum property, Elementary particles (Quarks, electrons, photons, etc.), composite particles (protons, neutrons, mesons, etc.), and even atoms and molecules, behave like small magnets and refer to north or south (upward and downward spins). magnetic field..
“A paramagnetic material such as aluminum, which is a metal, External magnetic field Applies. Ferromagnets containing iron can exhibit finite magnetization even in the absence of a magnetic field because they have magnetic domains, “Souza explained.
Entropy is basically a measure of the accessible configuration or state of a system. The greater the number of accessible states, the greater the entropy. Austrian physicist Ludwig Boltzmann (1844-1906) used a statistical approach to determine the entropy of a system of macroscopic size with the number of possible microscopic configurations that make up its macroscopic state. Associated. “For paramagnetic materials, entropy embodies the distribution of probabilities that represent the number of upspins or downspins of the particles they contain,” says Souza.
In a recently published study, paramagnetic salts were compressed in one direction. “Applying uniaxial stress reduces the amount of salt. Because this process does not exchange heat with the environment, compression raises the temperature of the material adiabatically. As the temperature rises, the entropy rises. To maintain, the total entropy of the system constant must have a component of a local decrease in entropy that offsets the rise in temperature, resulting in a tendency for spins to align, leading to system magnetization. “I will,” said Souza.
The total entropy of the system remains constant and adiabatic compression causes magnetization. “Experimentally, adiabatic compression is achieved when the sample is compressed in less time than is required for heat relaxation. This is the typical time it takes for a system to exchange heat with the environment. “Souza said.
Researchers also suggest that adiabatic temperature rise can be used to investigate other interacting systems, such as the Bose-Einstein condensation of magnetic insulators and the dipole spin ice system.
Quote: Researchers have obtained an external magnetic field (July 29, 2021) obtained from https: //phys.org/news/2021-07-method-magnetizing-material-external-magnetic on July 29, 2021. We are proposing a method to magnetize a material without applying it. html
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