Refrigeration performance enhancement in the La(Fe,Si)13-based compounds.

The unusual combination of features characteristic of first- and second-order phase transitions in the La(Fe,Si)13-based compounds is discussed on the basis of density-functional electronic structure calculations. The authors show how a peculiar series of consecutive field-induced transitions, predicted by the electronic structure calculations, is realised in melt-spun La(Fe,Si)13 using a combination of a hydrostatic pressure and a negative pressure created by the interstitial insertion of hydrogen. As a result, the maximum entropy change and relative cooling power increase in La[Fe,Si](13)H(x) hydrides with increasing hydrostatic pressure.