ferromagnetic (rus. ферромагнетик) — substance or material, where ferromagnetism is observed, i.е. the effect of spontaneous magnetisation at the temperature below the Curie point.

Description

Ferromagnets are transition elements - Fe, Co, Ni, some rare earth elements (Gd, Tb, Dy, Ho, Er, Tm); metal binary and multicomponent alloys and compounds of the metals above with each other and with other nonferromagnetic elements; Cr and Mn alloys and compounds with nonferromagnetic elements; amorphous alloys, including metal glass, for example, (80% Fe, 20% B); some actinide compounds, for example, UH3; dilute paramagnetic atom substitution solutions, for example, Fe or Co, in Pd matrix, and a number of oxide compounds, such as EuO, La1-xCaxMnO5 (0.4 > x > 0.2).

Ferromagnets are divided into soft and hard magnetic. Soft materials have low coercivity (the field required to change the magnetisation of that material to zero) and low remanent magnetisation (the magnetisation in the zero field). Hard ones have higher coercive force and remanent magnetisation.

Hard magnetic ferromagnets are used primarily in the production of permanent magnets. Soft magnetic ferromagnets are used in electrical engineering (transformers, electric motors, generators, etc.), in devices that convert electromagnetic energy into mechanical energy and vice versa.

Illustrations

<div>Typical curve of a ferromagnetic's magnetic hysteresis. Vertical axis - magnetization <i>M</i>,
Typical curve of a ferromagnetic's magnetic hysteresis. Vertical axis - magnetization M, horizontal axis - magnetic field intensity HMs — saturation magnetization, Mr — remnant magnetization, Hc — coercive force.

Authors

  • Zaitsev Dmitry D.
  • Khokhlov Dmitry R.

Sources

  1. Ferromagnetism // Wikipedia, the free encyclopedia. — http://en.wikipedia.org/wiki/Ferromagnetism (reference date: 02.08.2010).
  2. Ferromagnetism // Chemical encyclopedia (in Russian). — www.chemport.ru/chemical_encyclopedia_article_4015.html (reference date: 02.08.2010).
  3. Magnetics // Chemical encyclopedia (in Russian). — www.chemport.ru/chemical_encyclopedia_article_1994.html (reference date: 02.08.2010).