Figure 78

Fig. 78: (Top) The variation of the percentage of the minority orthorhombic Pnnm phase with temperature. Full and empty symbols correspond to data sets collected with a slightly different .

(Bottom) The displacive P4₂/mnm Pnnm mechanism in the (001) plane in ErFe₄Ge₂. The arrows indicate the displacement field of the two Fe orbits (distorted tetrahedron). Atoms 1-4 (orbit 1) have only a ±x component. Atoms: 1'-4' (orbit 2) have a predominant ±y component.