Simulation of the magnetic and magnetocaloric properties of hydrides of the La(Fe$_{0.88}$Si$_{0.12}$)$_{13}$ compound by applying a negative pressure

Based on the model calculation, it has been shown that the effect of hydration of the ferromagnetic compounds La(Fe$_{0.88}$Si$_{0.12}$)$_{13}$H$_y$ is quantitatively adequately described by the introduction of a negative pressure. The calculations have been performed for compounds with hydrogen concentrations $y$ = 0, 0.5, 1.0, and 1.5. It has been found that these concentrations correspond to the pressures $P$ = 0, -0.95, -1.85, and -2.80 GPa, respectively. The calculated Curie temperature, magnetization, characteristics of the magnetocaloric effect, and other properties are in satisfactory agreement with experiment.