Magnetic structure antiferromagnetic

P. Griinberg, R. Schreiber, Y. Pang, M.B. Brodsky, and H. Sowers, Layered magnetic structures Evidence for antiferromagnetic coupling of Fe layers across Cr interlayers, Phys. Rev. Lett. 57, 2442 (1986). 

We shall illustrate this technique by application to two magnetic structures that exist in nature. Consider the rutile structure associated with the antiferromagnetic crystal MnF2. Figure 12-4 shows the non-... 

The rare earths in their dodecaborides have the 3 + oxidation state except for Yb and Tm which have an intermediate valence state. A recoilless y-ray emission spectrum study of TmB,2 shows no magnetic ordering at 1.35 K the spectra of YbB,2 reveal no magnetic structure to 1.35 K. The compounds HoB,2, ErB,2 order antiferromagnetically, and ZrB,2 and LuB,2 become superconducting < 5.8 K and < 0.48 K, respectively. ... 

Figure S6.1 Magnetic structures (a) paramagnetic solid, (b) ferromagnetic ordering, (c) antiferromagnetic ordering, and (d) ferrimagnetic ordering. The magnetic dipoles on atoms are represented by arrows.

In the antiferromagnetic state, the spins are oriented parallel to the c-axis. Moss-bauer studies have indicated that the number and type of subsites in the magnetic structure may be influenced by the halide concentration, the nature of the halide and the level of excess protons vhich balance the halide charge. When chloride is present in the structure, there are tv o different Fe " sites, vhereas for fluoride-containing akaganeite, the number of non-equivalent cation sites may be greater. 

Fig. 26. Different types of magnetic structures in the ground stale of ftNijI C compounds, (a) For R = Pr, Dy or Ho commensurate antiferromagnelic structure, (b, c and d) for R = Er, Tb and Tm incommensurate antiferromagnetic structures (spin density waves) with a propagation vector q in the (a, 6)-plane, (b) Moments in the (a, b) plane and X to q. (c) Moments in the (a, b) plane and q. (d) Moments c and X to q (after Lynn et al.

Fig. 39. The different magnetic structures of HoNi2 B2C as determined by neutron scattering, (a) Commensurate antiferromagnetic, (b) incommensurate restructure (spiral) with the modulation vector T2 = (0.0,0.916) and (c) proposal how the incommensurate a -structure looks like (Loewenhaupt et al. 1997). Its modulation vector is...

It is obvious that the commensurate antiferromagnetic structure of fig. 39a coexists with superconductivity in HoNi2B2C, similar as in DyNi2B2C. On the other hand, as can be seen in fig. 43(a and c) the superconductivity is suppressed in the small temperature range where the two incommensurate magnetic structures of fig. 39(b and c) occur. Now the question is which of these two structures is more relevant for the near-reentrant behaviour. In Y().i5Hoo.85Ni2B2C the situation is totally different (fig. 43(b and d)). Here the a ... 

As reported by Blanco et al. (1999), neutron diffraction patterns of powder and bulk polycrystalline samples of GdCu were obtained for both structures in the cubic CsCl type of structure, which orders antiferromagnetically at 7n 150 K, a propagation vector of ( j 0) has been found with the moments probably parallel to the c-axis (note that other noncollinear magnetic structures might give rise to the same neutron-diffraction pattern). In the orthorhombic low temperature phase (7n 45 K) the available diffraction patterns... 

Fig. 33. Magnetic structure of GdCu2, the different symbols denote atoms belonging to the same ac plane, for simplicity the copper atoms are not shown. The magnetic structure can be viewed as a superposition of three simple antiferromagnetic lattices as indicated by the numbers (Rotter et al. 2000a).

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