Influence of H and Extra La on Magnetocaloric Effect of La$_{0.5 + x}$ Pr$_{0.5}$ Fe$_{11.4}$ Si$_{1.6}$ Melt-Spun Ribbons

Magnetic properties and magnetocaloric effect were investigated on La
_0.5+x
Pr
_0.5
Fe
_11.4
Si
_1.6
H
_y
(
x
=0, 0.1, 0.2) melt-spun ribbons. It was found that NaZn
₁₃
-type phase could be obtained easily owing to that the segregation of α-Fe phase was suppressed obviously by adding appropriate amount of La after a short time annealing for melt-spun ribbons. For the La
_0.6
Pr
_0.5
Fe
_11.4
Si
_1.6
H
_y
ribbons, the Curie temperature was adjusted dramatically from low temperature of 193 K to room temperature of 321 K due to the interstitial hydrogen adsorption. With La content increasing, Curie temperature was slightly increased; the magnetic hysteresis was reduced, while a large magnetic entropy change remained. The maximum magnetic entropy change (- Δ
SM
) is 33.8 J/(kg·K) for La
_0.6
Pr
_0.5
Fe
_11.4
Si
_1.6
while that of La
_0.6
Pr
_0.5
Fe
_11.4
Si
_1.6
H
_y
is 19.6 J/(kg·K) in a magnetic field change of 5 T. It is shown that rapid quenching to make LaFe
_13-x
Si
_x
alloys is more cost effective than arc melting method by reducing annealing time substantially. High magnetic entropy change and low magnetic hysteresis were obtained by adding extra La and the Curie temperature was tuned to near room temperature by interstitial atom H. This work indicated that La
_0.6
Pr
_0.5
Fe
_11.4
Si
_1.6
H
_y
was a promising magnetic refrigeration material near room temperature.