Influence of Supercooling on the Thermally Induced First-Order Magnetic Transition in Magnetocaloric Compound La(Fe$_{0.88}$Si$_{0.12}$)$_{13}$

Supercooling behavior in the thermally induced first-order transition from the paramagnetic (P) to ferromagnetic (F) phase is clarified for La(Fe
_0.88
Si
_0.12
)
₁₃
. The degree of supercooling is about 0.17 K at a cooling rate of -3.0 mK/s and exhibits a slight increase against the cooling rate, indicating the heterogeneous nucleation. On the other hand, the retaining time for the plateau-like behavior of the sample temperature after supercooling strongly depends on the cooling rate in inverse proportion. From these differences, the driving mechanism of the nucleation and growth of the F phase in the P matrix is elucidated. The influence of supercooling on the transition progress is also evaluated from the viewpoint of practical operation of a magnetic refrigerator.