Antiferromagnetic chain behavior

With a few exceptions, the crystal structure of the salts based on the type I mixed chains consists of parallel arrangements of those chains. In most cases the magnetic behavior of these salts is dominated by ferromagnetic (FM) interactions, due to intrachain D+ A coupling. Several of these salts exhibit metamagnetic (MM) behaviors due to the coexistence of weaker antiferromagnetic (AF) intrachain interactions. 

Most of the salts based on decamethylmetallocenium radical cations and on planar metal bisdichalcogenate radical anions reported so far present crystal structures with mixed linear chain basic motives. The only known exception is [Fe(Cp )2][Ni (mnt)2], which exhibits another type of crystal structure based on a D+ [A2]2 D+ repeat unit [28]. In the case of this compound the magnetic behavior is dominated by the intradimer antiferromagnetic interactions. 

The nickelates R2BaNi05 with RY, Nd-Gd, Dy-Tm feature antiferromagnetic S=1 Ni2+ chains interconnected by either nonmagnetic (R=Y) or magnetic (R=RE) ions. Recently, they attracted a considerable attention as model systems to study the ID magnetism, ID to 3D crossover, and the behavior of the Haldane-gap excitations through this crossover, as... 

Hydrates. A2MnmF5 H20 compounds (A = K, Rb, Cs) are suitable examples of Heisenberg chain antiferromagnets. The 1-D behavior is enhanced by the ferrodistortive ordering of dj2 orbitals, antiparallel along the c direction. In the ab plane weak d°2 y2 interactions occur between the chains. 

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