Magnets have a capacity to attract metallic elements generating magnetic fields. These magnetic fields are created due to the movement of electric charges, where the atoms of the permanent magnets are aligned to achieve a larger magnetic field. If we put a magnet in a place that has a low temperature the magnetism will increase. This is because the molecules inside the magnet have lower kinetic energy, so consequently, they will move more slowly, facilitating the alignment of the particles. This fact will cause the magnetic field to be strengthened by the magnet, increasing both its magnetic properties and its attractive force.
On the one hand, a neodymium magnet will maintain its properties and correct operation down to -130ºC. On the other hand, ferrite magnets have a greater facility for demagnetization when they are at a lower temperature than at a higher temperature. This type of permanent magnet will lose its magnetic strength below -60ºC.
Like permanent magnets, electromagnets have a stronger magnetic field at low temperatures, since the cold decreases the resistance of the wire, increasing its current. The atoms in the magnets have a slower and more orderly vibration when cold, generating a stronger magnetic field and strength.
As we can see in the following graph the magnetic force decreases as the temperature increases.
As the temperature of the magnet's environment decreases the Br increases, in other words, the flux density remaining in the magnet once it has been magnetized is higher.
On the other hand, Hci can increase as much as double or triple its value. From the point of view of its magnetization, the field is required to lead to saturation of the magnet.
The best-known magnets that withstand low temperatures are known as superconducting magnets, they transfer electric current while maintaining the energy in its entirety, this great conductivity is usually intended for applications such as magnetic resonance, magnetic levitation trains, and particle accelerators.
Magnetic materials can be classified according to the magnetic properties due to the attraction field stimuli that the different materials have to various types of responses they give. These materials have the ability to attract or repel others.
Magnetic materials have different types of properties and structures depending on the type of magnetic material. There are two types of magnetic materials:
Soft materials: characterized by their ability to be easily magnetized and demagnetized.
Hard materials: characterized by their high resistance to demagnetization, so that, despite the removal of its magnetic field, it will not demagnetize.
Magnetic materials can be classified into diamagnetic, paramagnetic, ferromagnetic, antiferromagnetic, ferrimagnetic, supermagnetic and ferrite materials. However, the most commonly used are: ferromagnetism, paramagnetism, diamagnetism.
Ferromagnetism is a property possessed by some materials in which the electron spins, known as magnetic domain, are placed in parallel. In this case, the temperature affects it directly because it can alter the disorder if the temperature is increasing, all ferromagnetic materials have a characteristic temperature known as Curie temperature Tc.
Paramagnetism is the phenomenon that occurs when the molecules found in a substance have a stable magnetism. In the same way, it appears when materials become magnetized when they are in contact with an external magnetic field. This phenomenon appears when some electrons are not paired.
Properties of paramagnetic materials:
Unlike ferromagnetic materials, if the magnetic field disappears, the magnetic properties that the magnet has will disappear with it.
Their magnetization is weak and temporary. Moreover, ferromagnetic materials are magnetized in the same direction.
They have a magnetic permeability >1.
Diamagnetism is the property of some materials to repel magnetic fields.
Diamagnetism was discovered by Sebald Justinus Brugmans who devoted himself to study the elements of the periodic table, more specifically: bismuth and antimony. Soon after, he realized that these elements were mutually rejecting each other as a consequence of magnetic fields.
Diamagnetic materials must have the following characteristics:
- To have all the electrons paired
- To conserve a relative permeability greater than 1
- Possess a negative magnetic induction and susceptibility.
- Weak magnetization and in the opposite direction to the magnetic field.
Diamagnetic materials: water, helium, copper, gold, silicon, bronze.
Ingeniería Mágnetica Aplicada (IMA), a leading company in the magnetism sector in Spain and with more than 30 years of experience, provides the best magnetic solutions and is in continuous innovation, this being one of the strategic objectives of the company.
Currently, IMA is developing a research program, innovating in & nbsp; magnetic products and applications, which allow it to maintain its position among the best companies in the sector worldwide.
This year, IMA participates in the 8th edition of the Accelerate Creixement, public-private collaboration between the Diputació de Barcelona and PIMEC.
A project that helps to promote business development and identifies the different medium and long-term growth opportunities of the participating companies. Companies draw up a personalized and tailored growth and action plan.
IMA will actively participate for 9 months with the program to improve performance and execute the new proposals, together with a team of professionals in the different areas of business management.
This program will encourage IMA to bet and improve even more in aspects related to technological innovation, new lines of products and services marketed, optimizing the internationalization process, among other factors of success for the Business Growth.
All the lines of action that the Accelera el Creixement program contributes to IMA, will be focused on increasing the market share in Europe, the efficiency in the manufacturing process and improvements in the orientation to customer satisfaction, consolidating IMA as a benchmark company in the magnetism sector.
Bioelectromagnetism is a specialty of biological sciences that analyzes the production of magnetic fields generated by living beings. This event is found in all living beings, whether in the plant or animal world. Bioelectromagnetism can be found in the electrical impulse found in cell membranes, as well as in the electrical currents that circulate in nerves and muscles as a consequence of the electrical impulse.
Bioelectromagnetism studies in the area of medicine, more specifically in electrophysiology techniques. Electrophysiology is a test used by several physicians that allows them to obtain the diagnosis in patients suffering from cardiac alterations. Luigi Galvani, a physician, and physicist in the late 18th century was the first to note the contraction of a frog muscle in the same location where he had conducted experiments with electricity. Galvani at first linked it to animal electricity or currently known as galvanism. It was then that Galvani concluded that the muscle contraction was the response of the substance inside the nerve.
As we have said bioelectromagnetism has many applications in different sectors such as physics, molecular, and cellular biology among others. We can also find it in biomedical engineering, for the production of medical equipment and instruments and its use in the treatment of various diseases. Bioelectromagnetic therapy is the use of electromagnetic fields to anticipate diseases and preserve health. This treatment, at the moment when the electromagnetic field changes, is placed close to a conductive medium at the same time as the human body, it will induce electric currents.
One of the most important applications is in medicine and epidemiology. The most commonly used medical applications in bioelectromagnetism are those with low frequency, which can be classified into thermal and non-thermal. Thermal applications of low-frequency radiation are the best known and include radiofrequency hyperthermia, surgery, and lasers.
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