Reduction of hysteresis loss and large magnetocaloric effect in the C- and H-doped La(Fe, Si)13 compounds around room temperature

Abstract

The effects of the interstitial C and H atoms on the phase formation, the hysteresis loss, and magnetocaloric effects of the NaZn13-type La(Fe, Si)13 compounds are investigated. It is found that the annealing time to obtain a 1:13 structure is significantly reduced from 40 days for LaFe11.7Si1.3 to a week for LaFe11.7Si1.3C0.2. The introduction of C and H atoms can adjust Curie temperature to around room temperature and leads to the decrease in magnetic entropy change (ΔSM) and magnetic hysteresis loss due to the weakening of itinerant-electron metamagnetic transition. Large −ΔSM of 19.0 J/kg K at room temperature without hysteresis loss for LaFe11.7Si1.3C0.2H1.7 is obtained for a field change of 5 T.

Corrosion behavior and ΔS-T relation of LaFe13−−Co Si C compounds near room temperature

“…The highest Curie temperature T c of the LaFe 1 À x Si x compounds is about 262 K for x¼2.5 [4], so the La(Fe 1 À x Si x ) 13 compounds cannot be directly applied in room temperature magnetic refrigeration. Previous studies show that the T c can be shifted to room temperature by introduced interstitial H atoms, while MCE remains high [5,6]. Unfortunately, the hydrides are usually chemically unstable above 150°C.…”

Magnetocaloric refrigerant with wide operating temperature range based on Mn5−Ge3(Co,Fe) composite

“…Since then, the concept has matured into a commercial cooling technology; however, its use has been limited to mainly reaching cryogenic temperatures. Recently observed giant MCE near room temperature from Gd 5 Si 4Àx Ge x [2][3][4][5], La(Fe 1Àx Si x ) 13 [6][7][8][9][10], MnFeP(As, Ge, Si) [11][12][13] and Ni-Mn-X (X = In, Sn, Ga and Sb) [14][15][16][17][18] motivated development of practical magnetic refrigeration system based on MCE operating near room temperature. Especially, with advent of global warming and foreseeable future shortage of fossil fuels, MCE-based magnetic refrigeration has attracted increasing attention because magnetic refrigeration, in theory, can outperform the conventional compression-vaporization cooling system in terms of energy efficiency without the use of volatile organic compounds and ozone-depleting refrigerants [14].…”

In-situ neutron investigation of hydrogen absorption kinetics in La(Fe Si1−)13 magnetocaloric alloys for room-temperature refrigeration application

“…A significant enhancement in desorption temperature of H was observed in the hydrided LaFe 11.6 Si 1.4 C x samples with x¼ 0.1 and 0.2 [15]. The investigation of hydrogen sorption properties in La 0.7 Pr 0.3 Fe 11.5 Si 1.5 C 0.2 showed that the addition of interstitial carbon atom, not only slows down hydrogen absorption, but also prevents hydrogen from being released [16,17]. In this respect, a knowledge of the interstitial insertion scheme is profitable and has prompted the current investigation.…”