Thermodynamics of the Exchange Inversion Transition of Cr-ModifiedMn2Sb

Compounds of the composition ${\mathrm{Mn}}_{2-x}{\mathrm{Cr}}_x\mathrm{Sb}$ show a first-order ferrimagnetic-to-antiferromagnetic phase transition for decreasing temperature with the transition temperature increasing as $x$ increases. Thermodynamic equations describing the transition were derived by considering ${\mathrm{Mn}}_{2-x}{\mathrm{Cr}}_x\mathrm{Sb}$ as a continuous family of one-component systems rather than a two-component equilibrium system. This first-order transition and the effects of magnetic field, stress, and composition were studied by measurements of the discontinuities in length, magnetization, and electrical resistance. Thermodynamic properties were derived from the data reported here and the data of other investigators. Calculations based on the derived thermodynamic equations agree with the experimental results.