Magnetism Curie temperature

Keywords XRD Magnetic Properties Magnetization Curie Temperature. 

Fig. 22. Saturation magnetization, Curie temperature Tc and re-ordering temperature TR with x for Fe3 MnxSi alloys (Yoon and Booth 1977).

A = Ca +, SP") crystal close to the magnetic Curie temperature. Details of the curve depend on temperature and concentration, (b) The low-field magnetoresistance of... 

EPR electron paramagnetic resonance Tc magnetic Curie temperature... 

Ino] Vickers microhardness tester, Instron-type tensile testing machine, magnetic balance, B-H tracer, impedance analyzer Hardness, tensile fracture strength, magnetization. Curie temperature, coercive field, permeability annealed and quenched C-Fe-Si melts... 

Tc magnetic Curie temperature superconducting AEq quadrupole splitting parameter... 

Tensile strength (rapidly-quenched ribbons 60 xm thick) Saturation magnetization Curie temperature Saturation magnetostriction... 

Phase Nature of magnetism Curie temperature or temperature (K) Reference... 

Nie] Nieholson, M.E., Solubihty of Boron in FesC and Variation of Saturation Magnetization, Curie Temperature, and Lattiee Parameter of Fe3(B,C) with Composition , Trans-AIME (J. Metals), 209, 1-6 (1957)... 

Equation (A2.5.20) is the Curie-Weiss law, and the temperature at which the magnetic susceptibility becomes infinite, is the Curie temperature. Below this temperature the substance shows spontaneous magnetization and is ferromagnetic. Nonnally the Curie temperature lies between 1 and 10 K. However, typical ferromagnetic materials like iron have very much larger values for quantum-mechanical reasons that will not be pursued here. 

Fig. 4. The effect of temperature for Mng 6 Zng 3 Fe Fe on (a) initial magnetic permeabiUty, )J., measured on a polycrystalline toroid appHed as a core for a coil driven by a low (B <0.1 mT) ampHtude, low (10 kHz) frequency sinusoidal signal and (b) magnetocrystalline anisotropy constant, measured on a monocrystalline sphere showing the anisotropy/compensation temperature Tq and the Curie temperature, T. To convert joules to calories, divide by...

From the write and read process sketched so far, some requirements for MO media can be derived (/) a high perpendicular, uniaxial magnetic anisotropy K in order to enable readout with the polar Kerr effect (2) a magnetoopticady active layer with a sufficient figure of merit R 0- where R is the reflectivity and the Kerr angle (T) a Curie temperature between 400 and 600 K, the lower limit to enable stable domains at room temperature and the upper limit because of the limited laser power for writing. 

The magnetic moments of the heavy RE elements (Gd, Tb, Dy, etc) are coupled antiparallel to the magnetic moments of the TM elements (Fe, Co, etc). The REj TM alloys are therefore ferrimagnetic below their Curie temperature (T )- The heavy TM moments form one magnetic sublattice and the RE moments the other one. In contrast, the light RE moments (eg, Nd, Pr) couple parallel to the moments of TM. The RE spia is always antiparallel to the TM spia, but for the light RE elements, the orbital momentum is coupled antiparallel to the spia and larger than the spia. 

Some of the composition adjustments in the Alnicos result in a high Curie temperature so that the decomposition reaction can take place relatively rapidly below This is particularly tme for Co, which is 24 wt % or greater for the anisotropic magnets. Another important consideration is the suppression of nonmagnetic fee y-phase which may appear at 1000—1100°C in this regard, the amount of Al, which is a y-suppressor, is critical. The formation of y is pronounced if the Al content falls much below 7—8 wt %. 

Cementite, the term for iron carbide in steel, is the form in which carbon appears in steels. It has the formula Fe C, and thus consists of 6.67 wt % carbon and the balance iron. Cementite is very hard and britde. As the hardest constituent of plain carbon steel, it scratches glass and feldspar, but not quart2. It exhibits about two-thirds the induction of pure iron in a strong magnetic field, but has a much lower Curie temperature. 

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