Anti-Invar behavior in enhanced paramagnets

We propose that strongly paramagnetic systems can show anti-Invar behavior. This is concluded from the model of Invar behavior and from the differences in calculated total energy, in magnetic pressure and equilibrium volume for nonmagnetic and ferromagnetic states. Self-consistent linear-muffin-tin-orbital calculations are performed for nonmagnetic and constrained magnetic configurations for ${\mathrm{ZrV}}_2$, ${\mathrm{ZrZn}}_2$, and ${\mathrm{TiBe}}_2$ in C15 structure at different volumes. It is found that the ground state is nonmagnetic in anti-Invar systems but low moment states are close in energy and have larger volumes. Model calculations based on thermal, magnetic fluctuations give the qualitative trends for the magnetovolume effects. It is discussed how optimal conditions for large anti-Invar anomalies should appear.