Lanthanoid zirconates Ln₂Zr₂O₇ (Ln = La, Pr, Nd, Sm, Eu) adopt the cubic pyrochlore structure (Fd3m, Z = 8), with cubic unit-cell edge a = 10.80 Å (La), 10.69 Å (Pr), 10.67 Å (Nd), 10.59 Å (Sm), 10.55 Å (Eu). Use this information, Equation (8.13) and Table 8.2 to estimate the dielectric permittivity of these phases. Does the Clausius–Mossotti equation predict that the dielectric constant will increase or decrease asthe radius of the rare-earth ion decreases?

Equation (8.13)

Table 8.2

Transcribed Image Text:

3 a -V 4 (r + 2) [CGSes : a in A, V in A] Er