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Assuming the external magnetic field is uniform and shares a common axis with the paramagnet, the extensive parameter characterizing the magnetic state is , the magnetic dipole moment of the system. The fundamental thermodynamic relation describing the system will then be of the form U = U ( S , V , I , N ) {\displaystyle U=U(S,V,I,N)} .
is the magnitude of the applied magnetic field (A/m), is absolute temperature , is a material-specific Curie constant (K). Pierre Curie discovered this relation, now known as Curie's law, by fitting data from experiment. It only holds for high temperatures and weak magnetic fields.
Here μ 0 is the permeability of free space; M the magnetization (magnetic moment per unit volume), B = μ 0 H is the magnetic field, and C the material-specific Curie constant: = (+), where k B is the Boltzmann constant, N the number of magnetic atoms (or molecules) per unit volume, g the Landé g-factor, μ B the Bohr magneton, J the angular ...
The Curie temperature of nanoparticles is also affected by the crystal lattice structure: body-centred cubic (bcc), face-centred cubic (fcc), and a hexagonal structure (hcp) all have different Curie temperatures due to magnetic moments reacting to their neighbouring electron spins. fcc and hcp have tighter structures and as a results have ...
These systems operate in a magnetic Brayton cycle, in a reverse way of the magnetocaloric refrigerators. [8] Experiments have produced only extremely inefficient working prototypes, [ 9 ] [ 10 ] [ 11 ] however, thermodynamic analysis indicate that thermomagnetic motors present high efficiency related to Carnot efficiency for small temperature ...
In this experiment, a static magnetic field runs through a long magnetic wire (e.g., an iron wire magnetized longitudinally). Outside of this wire the magnetic induction is zero, in contrast to the vector potential, which essentially depends on the magnetic flux through the cross-section of the wire and does not vanish outside.
To a first order approximation, the temperature dependence of spontaneous magnetization at low temperatures is given by the Bloch T 3/2 law: [1]: 708 = ((/) /),where M(0) is the spontaneous magnetization at absolute zero.
In typical magnetic materials, the Steinmetz coefficients all vary with temperature. The energy loss, called core loss , is due mainly to two effects: magnetic hysteresis and, in conductive materials, eddy currents , which consume energy from the source of the magnetic field, dissipating it as waste heat in the magnetic material.