Antiferromagnetic transition

The general behaviour of the specific heat near a magnetic transition is illustrated in Fig. 3.6 for MnC03. This carbonate undergoes a paramagnetic to antiferromagnetic transition at 24.9 K as the temperature is lowered. 

The resistivities of the magnetic borides DyB, H0B12, ErB, and TmB, have been carefully measured by Gabani et al. (1999) for good quality crystals with low room temperature resistivities (10-30 p 2 cm) compared to the early work. Near the antiferromagnetic transition temperatures Tn, the resistivities all show small increases in the form of humps and then rapid drops as the temperature is lowered. This behavior can be explained as an initial increase in the resistivity attributed to the appearance of superzone boundaries within the Brillouin zone, followed by a decrease due to a reduction in spin scattering (Taylor and Darby, 1972 Fournier and Gratz, 1993). 

An early paper by Matthias et al. (1968) deals with the three compounds H0B12, ErBi2, and TmBi2, and reports antiferromagnetic transitions at Tn = 6.5, 6.5, and... 

An updated/refined list of the respective superconducting and antiferromagnetic transition temperatures for the RB12 phases is given in Table 1. 

FIGURE 6 The magnetic susceptibility of TbBso- The arrow indicates the antiferromagnetic transition at = 17 K (Mori and Tanaka, 1999a). 

Nature of the antiferromagnetic transition of RBso-type compounds... 

These results indicate that the antiferromagnetic transition in TbB44Si2 is actually of dimer-like nature, where non-magnetic substitution leads to broken pairs resulting in free spins (Mori, 2004). The antiferromagnetically coupled pairs do not feel the effects of dilution of other terbium sites, and therefore, are stable below Hq which is a unique value regardless of the doping content. 

The magnetic field dependence of the susceptibility of GdBisSis was determined for the field applied along the c-axis, see Figure 34. As is typical for antiferromagnetic transitions, the transition temperature Tn shifts to lower temperatures as the... 

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