Magnetic phase transitions in antiferromagnets

In some magnetic materials the laboratory conditions of temperature 

The phase transitions that build up such diagrams can be studied by neutron diffraction and by the measurement of magnetic susceptibility and heat capacity. However, their study by means of Mossbauer spectroscopy has particular advantages in that, as well as determining the changes in spin 

In Cs2FeCl5. HjO values of B f, B and B extrapolated to 0 K give values of exchange and anisotropy fields of Bg 6.5 T and B 0.2 T respectively. The sharp reduction in Bhf at the phase transitions reflects a reduction in S caused by increased fluctuations of the spins in these conditions. At these transitions, the energy needed to create spin excitations in the spin 

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Magnetic properties of FeC03 in the vicinity of the phase transition from antiferromagnetic to ferromagnetic [9, 10]... 

V.G. Bar yachtar, A.E. Borovik, V.A. Popov, Theory of intermediate state in antiferromagnets at the first order phase transitions in external magnetic field. Sov. Phys.-JETP Letters, 9, 634-637 (1969)... 

Recent work has helped to refine the understanding of the physical and magnetic properties of these systems. The synthesis, structure, polymorphism, and electronic and magnetic properties of the electride Rb(cryptand[2.2.2])e have been described. Depending on the manner of preparation and the temperature, the antiferromagnetic electride can display a range of elecrical conductivity, from poor (<10 " Scm )—consistent with localized electrons— to near-metallic electrical conductivity. Studies of the phase transitions in Cs+(18-crown-6)2e with NMR, EPR, and variable-temperature powder X-ray diffraction indicates that it undergoes a slow irreversible... 

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