Large Isotropic Volume Change due to Thermal-induced First-order Transition in La1-zPrz(Fe0.88Si0.12)13

NaZn13-type La0.5Pr0.5(Fe0.88Si0.12)(13) exhibits an isotropic volume change associated with the thermal-induced first-order transition at the Curie temperature T-C = 186 K. The magnitude of the isotropic volume change at T-C of La0.5Pr0.5(Fe0.88Si0.12)(13) is about 1.3 %, larger than that of La(Fe0.88Si0.12)(13). As a result, the enhancement in the local magnetic moment of Fe at T-C is caused by the partial substitution of Pr. The volume change around T-C of La1-zPrz(Fe0.88Si0.12)(13) is comparable in magnitude to that of La1-z'Cez'(Fe0.88Si0.12)(13) having the same T-C. Accordingly, the enhancement in the local magnetic moment of Fe at T-C for La1-zPrz(Fe0.88Si0.12)(13) is closely related with the decrease of T-C without the marked decrease of thermal stability of Fe moment.