Antiferromagnetic Ferrimagnetic Transition

In the case of Mn2Sb, it was shown that Cf cAf is anticipated, or that compatibility with the model requires p 0. 

Since the sign of the first term is invariant with the sign of the interaction and p 0, is parallel to MB if ct cc and Ma is antiparallel to Mb if ct cc. There occurs a first-order anti ferromagnetic ferrimagnetic phase transition at a temperature Te such that 

Note that the sign of the interaction depends upon cr, not c. 

If f is the angle between M,i and Mb, the term in cos2 4 in equation 179 acts as a potential barrier separating the two states. It may introduce thermal hysteresis at the transition as large as 

The effect of hydrostatic pressure p on Te can be simply determined with the aid of the Clausius-Clapeyron equation. Kittel derives 

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Such an antiferromagnetic ferrimagnetic transition has been observed (120,122,609) in the system Mn2-xCrzSbo.95ln0.o5. Apparently the decrease in lattice parameter with increasing Cr content is sufficient that a Te is observed for x > 0.03, Te increasing from about 120°K to nearly 400°K at x = 0.2. For x = 0.1, the change in lattice parameter at Tt is Ac = 0.014 A. From equation 178 and reasonable estimates of the stiffness constant R it follows that... 

The temperature T of the antiferromagnetic-ferrimagnetic transition in single crystals at... 

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