Antiferromagnet a-

KCuFj is a ID antiferromagnet (A type) with the spins lying in the ab plane. The magnetic behaviour is again a consequence of antiferrodistortive ordering of distorted octahedra. Interaction between two half-filled orbitals occurs along the c axis... 

Fig. 28. Tentative phase diagram for LaMnC)3+5, 0 < <5 < 0.18. Data from Topfer and Goodenough (1997b). PI = paramagnetic insulator, CAFI = canted-spin antiferromagnetic (A-type) insulator, SGI = spin-glass insulator, FI = ferromagnetic insulator, MCS = metamagnetic canted-spin configuration.

Besides the theory of domain structure in antiferromagnets [18] - [21], similar to that of the intermediate state in type 1 superconductors, the suggestion was made [9], [10], that in antiferromagnets a state may be... 

Fig. 9a, b If the axes of the Jahn-Teller distortion of the two adjacent C60 ions coincide, then the coupling is antiferromagnetic (a). If they are orthogonal, the coupling should be ferromagnetic (b)... 

The existence of a critical point in the pressure-volume-temperature (PVT) diagram (actually, a point in the planar PV projection, but a critical line in a three-dimensional representation), a critical point (Curie temperature) in ferromagnetism, a critical point (Neel point) in antiferromagnetism, a critical temperature in superconductivity, and a critical point (lambda point) in liquid 2He4 are physical descriptions of the onset of a sudden macroscopic collective transition. If one approaches the critical point very closely, dimensionless parameters, defined to describe this approach, are common to all these disparate phenomena the approach to criticality, or to a phase transition, are really the same. 

M. S. Makivic and H. Q. Ding (1991) Two-dimensional spin-1/2 Heisenberg antiferromagnet A quantum Monte Carlo study. Phys. Rev. B 43, p. 3562... 

Antiferromagnetism - A type of magnetism in which the magnetic moments of atoms in a solid are ordered into two anti-paraUel aligned sublattices. Antiferromagnets are characterized by a zero or small positive magnetic susceptibility. The... 

Figure 6. (o) Volume fraction of phases as a function of temperature in Ndo.sSro.sMnOs- Open diamonds, open circles and open squares represent ferromagnet (FM), antiferromagnet (A-type, A-AF) and antiferromagnet (CE-type, CO-CEAF), respectively, (ft) Phase fractions at 125 K at different magnetic fields (i) 0 T and (ii) 6 T (iii) and (iv) show the magnetic moment in each of the phases ((o) after Woodward et al. (1999) and (ft) after Ritter et al. (2000)). 

Variable temperature magnetization studies also show an excellent fit for an S = 2 model, which indicates that the exchange coupling is large and antiferromagnetic. A J value of -89 cm l was estimated based on H = 2/ Si S2 (to be published). 

---