AuCd type

Fig. 30. Computed energy difference curve for the pair of structure types WC and AuCd for transition-metal transition metal alloys. The dashed line shows where examples of the AuCd type are experimentally found...

Here, Bq is the bulk modulus and Bq is its pressure derivative. The solid line in Figure 1 shows the result of fitting, in which the observed data are well reproduced. The obtained values are Vq = 42.68 A, Bq = 69.7 GPa, and Bq = 3.97. It is interesting to note that the initial compressibility is very close to the average compressibility of Gd and Cu elements. The authors suggested possible crystal structural transformation above 11 GPa to a low-symmetry structure. This result confirms the hypothesis of Degtyareva et al. (1997) in which the existence of an orthorhombic structure with the AuCd-type at high pressure has been proposed. 

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