Magnetic properties and magnetocaloric effect in La{sub 0.7}Nd{sub 0.3}Fe{sub 13-x}Si{sub x} compounds

The structural, magnetic and magnetocaloric properties in the cubic NaZn{sub 13}-type La{sub 0.7}Nd{sub 0.3}Fe{sub 13-x}Si{sub x} compounds with x=1.2, 1.4, 1.6 and 1.8 are reported. All of the investigated samples are ferromagnetically ordered. The Fe saturation moment at 5 K is independent of Si concentration, having a value of 2.05{+-}0.09 {mu}{sub B}, which suggests a high degree of localization. The Curie temperatures increase almost linearly with the increase in silicon concentration. The large {Delta}S{sub M} values obtained for samples with low Si content are mainly due to the first-order character of the transition at T{sub C}. The field-induced transition above T{sub C} causes an asymmetric broadening of the {Delta}S{sub M} peak towards higher temperatures for higher applied fields. With increasing Si content, the first-order character of the transition at T{sub C} is diminished, leading to lower {Delta}S{sub M} values. The potential use of these materials in magnetic refrigeration is discussed. - Graphical abstract: Transition from a first-order to a second-order magnetic phase transition at T{sub C} on La{sub 0.7}Nd{sub 0.3}Fe{sub 13-x}Si{sub x}. Highlights: Black-Right-Pointing-Pointer Magnetic properties and magnetocaloric effect in La{sub 0.7}Nd{sub 0.3}Fe{sub 13-x}Si{sub x} compounds are reported. Black-Right-Pointing-Pointer Transition from a first-order to a second-order type magnetic phase transitionmore » at T{sub C} with increasing silicon content. Black-Right-Pointing-Pointer Itinerant electronic metamagnetic transition above the Curie temperature. Black-Right-Pointing-Pointer High values of the magnetic entropy changes in 2 T magnetic field.« less