Magnetism: paramagnetic state

In order to figure out the FWs, the nuclear structure was refined from unpolarized neutron data taken at 30 K, in the paramagnetic state, on a 4-circle diffractometer. Furthermore, a set of 248 flipping ratios was measured with polarized neutrons at 1.6 K, with the spin density long range ordered by a 4.65 T applied magnetic field. 

Above a temperature called the Curie temperature, Tc, all ferromagnetic materials become paramagnetic. The transition to a paramagnetic state comes about when thermal energy is greater than the magnetic interactions and causes the dipoles... 

Figure 2.9 The B-Tphase diagram of MnP [13] with the magnetic field along the b-axis. Three different magnetically ordered phases - ferro, fan and screw - are separated by first-order phase transitions. The transitions to the disordered paramagnetic state are of second order and given by a dashed line.

Mott transition, 25 170-172 paramagnetic states, 25 148-161, 165-169 continuum model, 25 159-161 ESR. studies, 25 152-157 multistate model, 25 159 optical spectra, 25 157-159 and solvated electrons, 25 138-142 quantitative theory, 25 138-142 spin-equilibria complexes, 32 2-3, see also specific complex four-coordinated d type, 32 2 implications, 32 43-44 excited states, 32 47-48 porphyrins and heme proteins, 32 48-49 electron transfer, 32 45-46 race-mization and isomerization, 32 44—45 substitution, 32 46 in solid state, 32 36-39 lifetime limits, 32 37-38 measured rates, 32 38-39 in solution, 32 22-36 static properties electronic spectra, 32 12-13 geometric structure, 32 6-11 magnetic susceptibility, 32 4-6 vibrational spectra, 32 13 summary and interpretation... 

At high temperatures, ferroelectric materials transform to the paraelectric state (where dipoles are randomly oriented), ferromagnetic materials to the paramagnetic state, and ferroelastic materials to the twin-free normal state. The transitions are characterized through order parameters (Rao Rao, 1978). These order parameters are characteristic properties parametrized in such a way that the resulting quantity is unity for the ferroic state at a temperature sufficiently below the transition temperature, and is zero in the nonferroic phase beyond the transition temperature. Polarization, magnetization and strain are the proper order parameters for the ferroelectric. 

---