Heterogeneous nucleation and heat flux avalanches in La(Fe,Si)$_{13}$   magnetocaloric compounds near the critical point
  The phase transformation kinetics of LaFe$_{11.41}$Mn$_{0.30}$Si$_{1.29}$-H$_{1.65}$ magnetocaloric compound is addressed by low rate calorimetry experiments. Scans at 1 mK/s show that its first order phase transitions are made by multiple heat fllux avalanches. Getting very close to the critical point, the step-like discontinuous behavior associated with avalanches is smoothed out and thermal hysteresis disappears. This result is confirmed by magneto-resistivity measurements and allows to measure accurate values of the zero field hysteresis ($\Delta T_{hyst}$ = 0.37 K) and of the critical field (H$_c$ = 1.19 T). The number and magnitude of heat flux avalanches change with magnetic field, showing the interplay between the intrinsic energy barrier between phases and the microstructural disorder of the sample. 
C. Bennati, L. Gozzelino, E. S. Olivetti, V. Basso
cond-mat.mtrl-sci