Curie temperature


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Curie temperature

The critical or ordering temperature for a ferromagnetic or a ferrimagnetic material. The Curie temperature Tc is the temperature below which there is a spontaneous magnetization M in the absence of an externally applied magnetic field, and above which the material is paramagnetic. In the disordered state above the Curie temperature, thermal energy overrides any interactions between the local magnetic moments of ions. Below the Curie temperature, these interactions are predominant and cause the local moments to order or align so that there is a net spontaneous magnetization.

In the ferromagnetic case, as temperature T increases from absolute zero, the spontaneous magnetization decreases from M0, its value at T = 0. At first this occurs gradually, then with increasing rapidity until the magnetization disappears at the Curie temperature. In ferrimagnetic materials the course of magnetization with temperature may be more complicated, but the spontaneous magnetization disappears at the Curie temperature.

In antiferromagnetic materials the corresponding ordering temperature is termed the Néel temperature. Below the Néel temperature the magnetic sublattices have a spontaneous magnetization, though the net magnetization of the material is zero. Above the Néel temperature the material is paramagnetic. See Antiferromagnetism

The ordering temperatures for magnetic materials vary widely. The ordering temperature for ferroelectrics is also termed the Curie temperature, below which the material shows a spontaneous electric moment. See Ferromagnetism, Pyroelectricity

Curie temperature

[′kyu̇r·ē ‚tem·prə·chər]
(electromagnetism)
The temperature marking the transition between ferromagnetism and paramagnetism, or between the ferroelectric phase and paraelectric phase. Also known as Curie point.
References in periodicals archive ?
2001) concurs with these findings, whereby both the Curie temperature for composition of [Ba.
The main limitation of the neodymium magnet is that it had a low Curie temperature, as low as 300[degrees]C.
Dr Turner and colleagues experimented with a modern-day hangi to see if the stones at the base of the pit could achieve the necessary Curie temperatures to reset their magnetisation - to prove they could be used as an alternative data source for their study.
In other cases the measurement is realized only for temperatures deep below Curie temperature.
If a material were designed so that its Curie temperature is just above the target temperature range in MFH such a material would stop dissipating heat at the target temperature.
Figure 1 gives an example of the magnitude of this effect with Gadolinium, a rare-earth material that exhibits a strong effect and has a Curie temperature near typical room temperatures.
Figure 2 shows that magnetic materials exhibit a large magnetocaloric effect only over a narrow temperature range that is near the Curie temperature ([T.
Another example is a ferrite circulator, where even modest heating can bring the ferrite above the Curie temperature and disable it.
Although the sterilization temperature is well below the 300[degrees]C typical Curie temperature for PZT, the combination of pre-load and temperature result in a progressive degradation of piezo activity.
Magnetization of '1's and 'O's is carried out when the laser induced temperature is the Curie Temperature minus the ambient temperature.
Ancient scientists heated the stones using animal fats until they reached a special temperature known as the Curie temperature.