Antiferromagnetic compounds

This magnetic behavior is very sensitive to the chemical structure of the spin carrier and to the crystal packing. For instance, for the para-nitro substituted derivative, Nit(p-NO )Ph, which crystallizes in four different phases, the p phase only orders ferromagnetically (Tc = 0.6 K) [8,9], Moreover, attaching the nitro group in the meta-, rather than the / ara-position of the phenyl, leads to an antiferromagnetic compound [2],... 

Pickart, St. J., and H. A. Alperin Antiferromagnetic compounds containing ions with incomplete d-shell. Landolt-Bomstein-Tab. Vol. 2, Part. 9, p. 3 - 143 (1962). 

The magnetic effect due to the adsorption of oxygen is more difficult to explain. Per atom adsorbed this is within the limits of the accuracy equal to the effect of hydrogen. Now for the oxygen adsorption bond no connection with the d-character of the metal is generally assumed. At least in NiO the bond formation is considered as due to s-electrons. The magnetic moment per nickel atom in this antiferromagnetic compound is equal to that of the isolated nickel atom and corresponds to two unpaired d-elec-... 

The structures of the examined complexes are proved by x-ray diffraction, for example Refs. 115-117. Magnetochemical properties of these complexes, especially those of copper (mostly antiferromagnetic compounds), are reported in Refs. 104, 111, and 112. 

A spin-reduction property cannot be obtained for all the antiferromagnetic compounds. Thus, if ferromagnetic layers are weakly coupled antiferromagnetically, the zero-point spin-reduction will be negligible because the main interaction is the ferromagnetic one. The most impressive examples of spin reduction have been found in 2-D and 1-D Heisenberg antiferromagnetic fluorides. 

Alperin, H. A., and S. J. Pickart, Antiferromagnetic Compounds, Landolt-Bornstein Tabellen Vol. II/9 Springer-Vcrlag, Berlin-Gottingen-Heidelberg 1962, pp. 3-143. 

The larger unit cells necessary to account for the neutron diffraction data from antiferromagnetic compounds such as MnO are due to the antiparallel alignment of the magnetic moments of the metal ions. They are not to be confused with the larger unit cells of many superstructures which are due to ordered as opposed to random arrangement of atoms of two or more kinds. 

A study of the pressure dependence of of the antiferromagnetic compounds listed in table 2.2 shows that the initial pressure derivatives are positive in all cases. It is claimed frequently that the pressure variation of can be understood in terms of competing Kondo and RKKY interactions (see, e.g., Thompson et al. 1986). The negligible positive pressure effect on the magnetic moment of Np in NpCo2Si2 is an indication of localized magnetism in this compound. 

I) With antiferromagnetic compounds and D < 3.7 A. Such a boundary value coincides with the diameter of a trivalent Ce atom (see e.g. Koskenmaki and Gschneidner 1978). 

Antiferromagnetic compounds belonging to region I. The parameters are defined in the list of symbols. 

Stmcture data as well as pressure studies indicate that superconductivity in CeMIns occurs close to a quantum critical point (QCP). The lattice parameters suggest that the antiferromagnetic compound CeRhlns and the superconductor CeCoIns fall on different sides of the QCP in the Doniach phase diagram. 

In a novel antiferromagnetic compound, [Mn20a(bipy)JC10i,3Ha0, the metal atoms in the dinuclear cation are linked by two oxo-bridges. " The chelate portion of the cation and the appropriate bond lengths are shown in Figure 3. The compound is unusual in that the bonds around the metal... 

In this section we deal with ESR in metallic systems where the ESR-active probe is substituted at relatively high concentrations (i.e. more than 10%) or where the ESR probe is a constituent of the alloy itself, i.e. Gd metal, GdAgIn or GdA. In many of these alloys or compounds one can observe magnetic ordering. In such cases we consider only investigations of the resonance absorption above the Curie or Neel temperature, i.e. we do not include measurements on ferro-, ferri- or antiferromagnetic compounds. The demarcation line to resonance experiments in spin-glass systems in many cases is rather arbitrary. 

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