Coercive Force

Also found in: Dictionary, Wikipedia.

coercive force

[kō′ər·siv ′fȯrs]
The magnetic field H which must be applied to a magnetic material in a symmetrical, cyclicly magnetized fashion, to make the magnetic induction B vanish. Also known as magnetic coercive force.

Coercive Force


one of the characteristics of the phenomenon of hysteresis. In magnetic hysteresis the coercive force is the magnetic field intensity at which a ferromagnetic specimen that has been initially magnetized to saturation becomes demagnetized. A distinction is made between the coercive force JHc (or Hc) and the force BHc, when the magnetization J of the specimen or the magnetic induction B in the specimen becomes zero.

Coercive forces are measured by means of coercimeters. The values for ferromagnetic materials vary over a wide range, from 10-3 to 104 oersteds, or 8 x 10-2 to 8 x 105 amperes per meter (A/m). For a given magnetic material the coercive force depends to a large extent on the preparation of the specimen and on its treatment, as well as on external conditions, such as temperature. According to the magnitude of the coercive force, magnetic materials are customarily divided into magnetically soft materials (small Hc) and magnetically hard materials (large Hc). The value of the coercive force is determined by the factors that oppose remagnetization of the specimen. The presence of impurities, lattice defects, and various types of inhomogeneities in a specimen hinders the movement of domain walls and thus increases Hc.

Particularly high values of coercive force (103–104 oersteds) are achieved by single-domain ferromagnetic particles (with substantial magnetic anisotropy). The coercive force of ferroelectric materials is considered to be like that of ferromagnetic materials.

References in periodicals archive ?
Their stance amounts to a conscious challenge to their legal system's claim to a monopoly of coercive force, and insofar as it is successful, it will tend to undermine the legal peace afforded by that monopoly; not just for the friends themselves but for everyone else as well.
virtually no research grades of steel VSt3sp5 ([TEXT NOT REPRODUCIBLE IN ASCII]) for changes in the process of cycle fatigue indicators such as coercive force, hardness, coefficient of variation of hardness.
Variation in microstructure and hardness of roll were studied using coercive force and hardness measurement technique.
The adiaphoron in question is not being placed upon the church by coercive force, at least not the kind of coercive force addressed in Article X of the Formula, unless we conclude that an ecclesiastical vote is as threatening as a sword.
21) With God's left hand, God was struggling with coercive force against powers that threatened life itself.
We are an intergovernmental organization with a coercive force of solidarity, cooperation and political dialogue among its States and that constitutes a potential at different levels.
The African Union exerts coercive force, even though it may send peacekeeping missions," he said.
DeBoer could have used that money to save horses from slaughter by buying them herself, or she could have established a private foundation to raise awareness on this issue, instead of turning to the coercive force of government to legislate her personal crusade," Brown proposed.
Enterline overuses the pedagogical imperative: she commands her readers to "notice," "recall," and "consider" to a degree surprising in a study so attentive to the coercive force of language.
As the military build-up continues in the region around Afghanistan the might of the developed world's coercive force is being arrayed for all to see.
To make similar predictions where matrix structure also varies, measurement of eddy current, coercive force or hardness must be used in conjunction with either resonant frequency or ultrasonic velocity.
While such a chair may be useful, it can easily cross the line as a coercive force," wrote Criminal Court Judge Mary Beth Leibowitz.