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The magnetization of a magnetized material is the local value of its magnetic moment per unit volume, usually denoted M, with units A / m.
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magnetization and magnetized
Although this state of aligned domains found in a piece of magnetized ferromagnetic material is not a minimal-energy configuration, it is metastable, and can persist for long periods, as shown by samples of magnetite from the sea floor which have maintained their magnetization for millions of years.
Originally, in-plane magnetized materials were used to store the bits but perpendicular magnetization is now taking over.
Lightning-induced magnetic anomalies can be mapped in the ground ,< ref > and analysis of magnetized materials can confirm lightning was the source of the magnetization and provide an estimate of the peak current of the lightning discharge.
The cores can be magnetized in two different ways ( clockwise or counterclockwise ) and the bit stored in a core is zero or one depending on that core's magnetization direction.
The magnetic material for a core memory requires a high degree of magnetic remanance, the ability to stay highly magnetized, and a low coercitivity so that less energy is required to change the magnetization direction.
When a current was passed through the coil, the iron became magnetized and attracted other pieces of iron ; when the current was stopped, it lost magnetization.
T2 * decay is caused by magnetized nuclei in a volume of space losing magnetic coherence ( transverse magnetization ) from both bumping into one another and from intentional differences in applied magnetic field strength across locations ( field inhomogeneity from a spatial gradient ).
The magnetic tape was specifically selected to only allow magnetization along the length of the tape, so only a single point of the twistor would have the right direction of field to become magnetized.
This material has a wide hysteresis loop ( high retentivity ), meaning once it is magnetized in a given direction, it requires a large reverse magnetic field to reverse the magnetization.
The magnetization vectors in the magnetized sheets rotate in the opposite senses to each other ; above, the top sheet's magnetization vector rotates clockwise and the bottom sheet's magnetization vector rotates counter-clockwise.
Another class of design is the magnetic mangle ( B ), proposed by Coey and Cugat, in which uniformly magnetized rods are arranged such that their magnetization matches that of a Halbach cylinder, as shown for a six rod design.
He correctly deduced that this was caused by a damped oscillating discharge current in the wire, which reversed the magnetization of the needle back and forth until it was too small to have an effect, leaving the needle magnetized in a random direction.
The piece can be magnetized by direct or indirect magnetization.
The magnetization is normally done with a high current pulse that reaches a peak current very quickly and instantaneously turns off leaving the part magnetized.
In the 19th century studies of the direction of magnetization in rocks showed that some recent lavas were magnetized parallel to the Earth's magnetic field.
If a magnet is magnetized in a certain direction, each spin will fluctuate at any temperature, but the net magnetization will never change.
magnetization and material
Historically, the term ferromagnet was used for any material that could exhibit spontaneous magnetization: a net magnetic moment in the absence of an external magnetic field.
More recently, however, different classes of spontaneous magnetization have been identified when there is more than one magnetic ion per primitive cell of the material, leading to a stricter definition of " ferromagnetism " that is often used to distinguish it from ferrimagnetism.
In particular, a material is " ferromagnetic " in this narrower sense only if all of its magnetic ions add a positive contribution to the net magnetization.
If some of the magnetic ions subtract from the net magnetization ( if they are partially anti-aligned ), then the material is " ferrimagnetic ".
The net magnetization can be destroyed by heating and then cooling ( annealing ) the material without an external field, however.
* Permeability ( electromagnetism ) coefficient, degree of magnetization of a material
The other sources of magnetism are the nuclear magnetic moments of the nuclei in the material which are typically thousands of times smaller than the electrons ' magnetic moments, so they are negligible in the context of the magnetization of materials.
* Magnetic domain, a region within a magnetic material which has uniform magnetization
The local strength of magnetism in a material is measured by its magnetization.
Another model is the Ampère model, where all magnetization is due to the effect of microscopic, or atomic, circular bound currents, also called Ampèrian currents, throughout the material.
Diamagnetics are defined by the generation of a spontaneous magnetization of a material which directly opposes the direction of an applied field.
* Hysteresis losses: Reversing the direction of magnetization of the magnetic domains in the core material each cycle causes energy loss, because of the coercivity of the material.
* Permeability ( electromagnetism ), the degree of magnetization of a material in response to a magnetic field
In electromagnetism, the magnetic susceptibility ( latin: susceptibilis “ receptiveness ”) is a dimensionless proportionality constant that indicates the degree of magnetization of a material in response to an applied magnetic field.
A closely related parameter is the permeability, which expresses the total magnetization of material and volume.
: M is the magnetization of the material ( the magnetic dipole moment per unit volume ), measured in amperes per meter, and
In this case, the magnetic field in the material is strengthened by the induced magnetization.
As a result, the magnetic field in the material is weakened by the induced magnetization.
On magnetization, a magnetic material undergoes changes in volume which are small: of the order 10 < sup >− 6 </ sup >.
The property can be quantified by the magnetostrictive coefficient, L, which is the fractional change in length as the magnetization of the material increases from zero to the saturation value.
In physics, a ferrimagnetic material is one in which the magnetic moments of the atoms on different sublattices are opposed, as in antiferromagnetism ; however, in ferrimagnetic materials, the opposing moments are unequal and a spontaneous magnetization remains.
magnetization and is
The Ising model was solved exactly to show that spontaneous magnetization cannot occur in one dimension but is possible in higher dimensional lattices.
If the moments of the aligned and anti-aligned ions balance completely so as to have zero net magnetization, despite the magnetic ordering, then it is an antiferromagnet.
Ferromagnetism involves an additional phenomenon, however: the dipoles tend to align spontaneously, giving rise to a spontaneous magnetization, even when there is no applied field.
This is a dependence of the energy on the direction of magnetization relative to the crystallographic lattice.
This is shown by the Barkhausen effect: as the magnetizing field is changed, the magnetization changes in thousands of tiny discontinuous jumps as the domain walls suddenly " snap " past defects.
This magnetization as a function of the external field is described by a hysteresis curve.
When the temperature rises beyond a certain point, called the Curie temperature, there is a second-order phase transition and the system can no longer maintain a spontaneous magnetization, although it still responds paramagnetically to an external field.
The Curie temperature itself is a critical point, where the magnetic susceptibility is theoretically infinite and, although there is no net magnetization, domain-like spin correlations fluctuate at all length scales.
An MRI scanner is a device in which the patient lies within a large, powerful magnet where the magnetic field is used to align the magnetization of some atomic nuclei in the body, and radio frequency fields to systematically alter the alignment of this magnetization.
After the electromagnetic field is turned off, the spins of the protons return to thermodynamic equilibrium and the bulk magnetization becomes re-aligned with the static magnetic field.
If the field is small, the response of the magnetization in a diamagnet or paramagnet is approximately linear:
where the H-field is related to the B-field and the magnetization by
0.122 seconds.