La(Fe,Si)13-based magnetic refrigerants obtained by novel processing routes

The structure and magnetic properties of LaFe13−xSix and Co-substituted LaFe11.8−xCoxSi1.2 alloys prepared by melt spinning, as well as of LaFe11.57Si1.43Hx hydrides prepared by reactive milling are investigated. The hysteresis in the temperature- and field-induced phase transitions is significantly reduced as compared with conventional bulk alloys, which makes these materials very attractive for magnetic refrigerant applications. 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.