The Curie temperature
[T.sub.C3]~820 K for MVer and MMt samples corresponds to a ferromagnetic-paramagnetic transition of maghemite, [gamma]-[Fe.sub.2][O.sub.3],  and thereby supports the Mossbauer results.
Although these magnets achieved high-performance scores, they possess a marginal Curie temperature
in the range of 300-400[degrees]C with an operating temperature restricted to ~150[degrees]C plagued by both brittleness and a large propensity to corrode .
The values of the Curie temperatures
([T.sub.C]) were calculated from the minimum of dM/dT in the magnetization curve during the heating cycle (see inset of Figure 3).
It is a potential candidate to compete with the rare-earth PMs for magnetic gear application because it can offer the merits of high remanence, high Curie temperature
and very low cost [18,19].
It can be noticed that the pyrolysis reaction of oil shale is slow when the Curie temperature
is below 386[degrees]C, and becomes intense above 423[degrees]C.
As the current increases, the temperature of the reed blades increases until it reaches a temperature where the material is no longer ferromagnetic (Curie temperature
2C) of samples shows, in addition to magnetite (Curie temperature
[T.sub.C] = 550[degrees]C and Verwey transition [T.sub.Ver] = -158[degrees]C), three other distinct transitions: around 120, 340 and 620[degrees]C.
Among the topics are the technical viability of biocoke from mixtures of coal and wood charcoal for use in ironmaking, the effect of batch charging equipment on glass furnace efficiency, software for energy education, measuring the carbon dioxide captures on bauxite residue carbonation, anisotropic Curie temperature
material, and designing permanent magnet machines for ferrofluid immersion.
In fact, the Curie transition has been shown to vary with processing conditions and also with the concentration of VDF and TrFE [4, 22], A slight increase of the VDF contents around 70 mol% will lead to a significant increase in Curie temperature
but the melting temperature varies very slightly , The similar results to those observed in our study were reported by Green et al.
But because of low Curie temperature
, high stress sensitivity, and high cost of the garnets, they are rarely used.
Barium strontium titanate ([Ba.sub.x][Sr.sub.1-x]Ti[O.sub.3]/BST) material is one of the ferroelectric material which attract great interest among researchers to study its electrical properties due to high dielectric constant and composition dependent Curie temperature
A magnetocaloric material exhibits a strong magnetocaloric effect near the Curie temperature
, when the phase changes from paramagnetic to ferromagnetic.
The Curie temperature
is an important characteristic of a permanent magnet.
Table 1 Physical properties of gadolinium Quantity Value Curie temperature
293 K Density 7900 kg/[m.sup.3] (0.28 lb/[in.sup.3]) Heat capacity 230 J/kg-K Thermal 10.5 W/m-K conductivity Table 2 Physical properties of oxygen-freecopper Quantity Value Density 8880 kg/[m.sup.3] (0.31 lb/[in.sup.3]) Heat capacity 386 J/kg*K Thermal 398 W/m*K conductivity
(i) the value of [epsilon]' increases gradually with rise in temperature and reaches a maximum value at [[epsilon].sub.max] at a particular temperature known as Curie temperature