Magnetocaloric Effect

Also found in: Acronyms.

Magnetocaloric effect

The reversible change of temperature accompanying the change of magnetization of a ferromagnetic or paramagnetic material. This change in temperature may be of the order of 1°C (2°F), and is not to be confused with the much smaller hysteresis heating effect, which is irreversible. See Thermal hysteresis

McGraw-Hill Concise Encyclopedia of Physics. © 2002 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Magnetocaloric Effect


a change in the temperature of a magnetic substance upon an adiabatic change in the intensity H of the magnetic field in which the substance is located.

Energy of magnetization δ = JdH (where J is the magnetization) is achieved as the field changes by dH. According to the first law of thermodynamics, δA = δQ — dU, where δQ is the amount of heat imparted to a magnetic substance (equal to zero under adiabatic conditions) and dU is the change in the internal energy of the substance. Thus, when δQ = 0, work is accomplished only as a result of change in the internal energy (δA = —dU), which leads to a change in the temperature of the magnetic substance if its internal energy is dependent on temperature T. In paramagnetic and ferromagnetic substances, the magnetization J increases with H, that is, there is an increase in the number of atomic magnetic moments (spin or orbital) parallel to H. As a result, there is a reduction in the energy of paramagnets and ferromagnets with respect to the field and in their internal energy of exchange reaction. On the other hand, the internal energy of paramagnets and ferromagnets increases with T. Therefore, according to the Le Chatelier-Brown principle, heating of paramagnets and ferromagnets should take place on magnetization. For ferromagnets, this effect is at a maximum near the Curie point; for paramagnets, the magnetocaloric effect in-creases with a decrease in temperature. Upon an adiabatic reduction of the field, there is partial or total destruction (the latter when the field is shut off) of the ordered orientation of the moments at the expense of the internal energy. This leads to the cooling of the magnetic substance.


Vonsovskii, S. V. Magnetizm. Moscow, 1971.


The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.

magnetocaloric effect

[mag¦nēd·ō·kə′lȯr·ik i‚fekt]
The reversible change of temperature accompanying the change of magnetization of a ferromagnetic material.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
Gschneidner Jr., "Giant magnetocaloric effect in [Gd.sub.5]([Si.sub.2][Ge.sub.2])," Physical Review Letters, vol.
Synoradzki, "Specific heat and magnetocaloric effect of the [Mn.sub.5][Ge.sub.3] ferromagnet," Intermetallics, vol.
A magnetocaloric material exhibits a strong magnetocaloric effect near the Curie temperature, when the phase changes from paramagnetic to ferromagnetic.
The magnetocaloric effect causes the material in the bed to increase in temperature when it is magnetized.
In effect, the AMR cycle combines the magnetocaloric effect with a simple process in which fluid is cycled between the hot and cold ends of a regenerator.
Acet et al., "Magnetic superelasticity and inverse magnetocaloric effect in Ni-Mn-In," Physical Review B: Condensed Matter and Materials Physics, vol.
The magnetocaloric effect is a solid-state effect in which certain solid materials respond to a change in applied magnetic field with a temperature change.
Using these materials, it is possible to construct a layered regenerator bed that can achieve a high magnetocaloric effect across its entire operating temperature range.
The magnetocaloric effect depends on the way a material's atomic spins align themselves.
Magnetic refrigerators exploit the magnetocaloric effect -- the ability of some metals to become hot when magnetized and cool when demagnetized.
Another application under consideration by researchers at Xerox and elsewhere is solid-state magnetic refrigerators based on the magnetocaloric effect by which heat is reversibly absorbed and discharged when small ferromagnetic particles are aligned by magnetic fields.