A report on Magnetic field and Magnetization

The shape of the magnetic field produced by a horseshoe magnet is revealed by the orientation of iron filings sprinkled on a piece of paper above the magnet.
When the microscopic currents induced by the magnetization (black arrows) do not balance out, bound volume currents (blue arrows) and bound surface currents (red arrows) appear in the medium.
Right hand grip rule: a current flowing in the direction of the white arrow produces a magnetic field shown by the red arrows.
A Solenoid with electric current running through it behaves like a magnet.
A sketch of Earth's magnetic field representing the source of the field as a magnet. The south pole of the magnetic field is near the geographic north pole of the Earth.
One of the first drawings of a magnetic field, by René Descartes, 1644, showing the Earth attracting lodestones. It illustrated his theory that magnetism was caused by the circulation of tiny helical particles, "threaded parts", through threaded pores in magnets.
Hans Christian Ørsted, Der Geist in der Natur, 1854

Net magnetization results from the response of a material to an external magnetic field.

- Magnetization

In a vacuum, the two fields are related through the vacuum permeability, ; but in a magnetized material, the terms differ by the material's magnetization at each point.

- Magnetic field
The shape of the magnetic field produced by a horseshoe magnet is revealed by the orientation of iron filings sprinkled on a piece of paper above the magnet.

8 related topics with Alpha

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A "horseshoe magnet" made of alnico, an iron alloy. The magnet, made in the shape of a horseshoe, has the two magnetic poles close together. This shape creates a strong magnetic field between the poles, allowing the magnet to pick up a heavy piece of iron.

Magnet

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A "horseshoe magnet" made of alnico, an iron alloy. The magnet, made in the shape of a horseshoe, has the two magnetic poles close together. This shape creates a strong magnetic field between the poles, allowing the magnet to pick up a heavy piece of iron.
Magnetic field lines of a solenoid electromagnet, which are similar to a bar magnet as illustrated below with the iron filings
Iron filings that have oriented in the magnetic field produced by a bar magnet
Field of a cylindrical bar magnet computed accurately
Hard disk drives record data on a thin magnetic coating
Magnetic hand separator for heavy minerals
Magnets have many uses in toys. M-tic uses magnetic rods connected to metal spheres for construction.
A stack of ferrite magnets
Ovoid-shaped magnets (possibly Hematine), one hanging from another
Field lines of cylindrical magnets with various aspect ratios

A magnet is a material or object that produces a magnetic field.

The local strength of magnetism in a material is measured by its magnetization.

A magnet made of alnico, a ferromagnetic iron alloy, with its keeper

Ferromagnetism

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Basic mechanism by which certain materials form permanent magnets, or are attracted to magnets.

Basic mechanism by which certain materials form permanent magnets, or are attracted to magnets.

A magnet made of alnico, a ferromagnetic iron alloy, with its keeper
Electromagnetic dynamic magnetic domain motion of grain-oriented electrical silicon steel
Kerr micrograph of metal surface showing magnetic domains, with red and green stripes denoting opposite magnetization directions
Moving domain walls in a grain of silicon steel caused by an increasing external magnetic field in the "downward" direction, observed in a Kerr microscope. White areas are domains with magnetization directed up, dark areas are domains with magnetization directed down.

Permanent magnets (materials that can be magnetized by an external magnetic field and remain magnetized after the external field is removed) are either ferromagnetic or ferrimagnetic, as are the materials that are noticeably attracted to them.

An electrostatic analog for a magnetic moment: two opposing charges separated by a finite distance.

Magnetic moment

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An electrostatic analog for a magnetic moment: two opposing charges separated by a finite distance.
Image of a solenoid
Magnetic field lines around a "magnetostatic dipole". The magnetic dipole itself is located in the center of the figure, seen from the side, and pointing upward.
The magnetic field of a current loop

In electromagnetism, the magnetic moment is the magnetic strength and orientation of a magnet or other object that produces a magnetic field.

is the magnetization.

When liquid oxygen is poured from a beaker into a strong magnet, the oxygen is temporarily contained between the magnetic poles owing to its paramagnetism.

Paramagnetism

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When liquid oxygen is poured from a beaker into a strong magnet, the oxygen is temporarily contained between the magnetic poles owing to its paramagnetism.
Idealized Curie–Weiss behavior; N.B. TC=θ, but TN is not θ. Paramagnetic regimes are denoted by solid lines. Close to TN or TC the behavior usually deviates from ideal.

Paramagnetism is a form of magnetism whereby some materials are weakly attracted by an externally applied magnetic field, and form internal, induced magnetic fields in the direction of the applied magnetic field.

Illustration of a magnet with four magnetic closure domains. The magnetic charges contributed by each domain are pictured at one domain wall. The charges balance, so the total charge is zero.

Demagnetizing field

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[[File:VFPt magnets BHM.svg|thumb|Comparison of magnetic field (flux density)

[[File:VFPt magnets BHM.svg|thumb|Comparison of magnetic field (flux density)

Illustration of a magnet with four magnetic closure domains. The magnetic charges contributed by each domain are pictured at one domain wall. The charges balance, so the total charge is zero.

The demagnetizing field, also called the stray field (outside the magnet), is the magnetic field (H-field) generated by the magnetization in a magnet.

Magnetic hysteresis

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[[Image:StonerWohlfarthMainLoop.svg|thumb|right|400px|[[Stoner–Wohlfarth model|Theoretical model]] of magnetization

against magnetic field

Ferrimagnetic ordering

Ferrimagnetism

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Material that has populations of atoms with opposing magnetic moments, as in antiferromagnetism.

Material that has populations of atoms with opposing magnetic moments, as in antiferromagnetism.

Ferrimagnetic ordering
➀ Below the magnetization compensation point, ferrimagnetic material is magnetic. ➁ At the compensation point, the magnetic components cancel each other and the total magnetic moment is zero. ➂ Above the Curie temperature, the material loses magnetism.

[[Image:StonerWohlfarthMainLoop.svg|thumb|right|233x233px|[[Stoner–Wohlfarth model|Theoretical model]] of magnetization

against magnetic field

Gauss's law for magnetism: magnetic field lines never begin nor end but form loops or extend to infinity as shown here with the magnetic field due to a ring of current.

Maxwell's equations

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Maxwell's equations are a set of coupled partial differential equations that, together with the Lorentz force law, form the foundation of classical electromagnetism, classical optics, and electric circuits.

Maxwell's equations are a set of coupled partial differential equations that, together with the Lorentz force law, form the foundation of classical electromagnetism, classical optics, and electric circuits.

Gauss's law for magnetism: magnetic field lines never begin nor end but form loops or extend to infinity as shown here with the magnetic field due to a ring of current.
In a geomagnetic storm, a surge in the flux of charged particles temporarily alters Earth's magnetic field, which induces electric fields in Earth's atmosphere, thus causing surges in electrical power grids. (Not to scale.)
Magnetic-core memory (1954) is an application of Ampère's law. Each core stores one bit of data.
Left: A schematic view of how an assembly of microscopic dipoles produces opposite surface charges as shown at top and bottom. Right: How an assembly of microscopic current loops add together to produce a macroscopically circulating current loop. Inside the boundaries, the individual contributions tend to cancel, but at the boundaries no cancelation occurs.

The equations provide a mathematical model for electric, optical, and radio technologies, such as power generation, electric motors, wireless communication, lenses, radar etc. They describe how electric and magnetic fields are generated by charges, currents, and changes of the fields.

These bound currents can be described using the magnetization