Reduction of hysteresis losses in the magnetic refrigerant La0.8Ce0.2Fe11.4Si1.6 by the addition of boron

Abstract

In an effort to improve the magnetocaloric effects of the NaZn13-type La0.8Ce0.2Fe11.4Si1.6 compound, the effect of boron doping on the magnetic properties and magnetocaloric properties has been investigated. The magnetic entropy change (ΔSM) for the La0.8Ce0.2Fe11.4Si1.6 compound, obtained for a field change of 0–5 T using the Maxwell relation exhibits a spike and appears to be overestimated and is thus corrected by using the Clausius-Clapeyron equation (CC). The ΔSM determined from the CC equation is estimated to be 19.6 J kg−1K−1. However, large hysteretic losses which are detrimental to the magnetic refrigeration efficiency occur in the same temperature range. In this work, we report a significant reduction in hysteretic losses by doping the La0.8Ce0.2Fe11.4Si1.6 compound with a small amount of boron to obtain La0.8Ce0.2Fe11.4Si1.6Bx compounds. The hysteresis loss decreases from 131.5 to 8.1 J kg −1 when x increases from 0 to 0.3, while ΔSM, obtained for a field change of 0–5 T, varies from 19.6 to 15.9 J kg−1K−1. This also simultaneously shifts the TC from 174 to 184 K and significantly improves the effective refrigerant capacity (RCeff) of the material from 164 to 305 J kg−1.

Enhanced magnetocaloric effect in Ni-Mn-Sn-Co alloys with two successive magnetostructural transformations

“…Noteworthily, the RC eff of the present Co6 alloy reaches 223 J/kg, which is significantly larger than those of the stoichiometric Ni-Mn-based alloys 18,45,76,77,79,81–84 and is comparable to those of some Co-doped Mn-rich Ni-Mn-based compounds 1,63,78–80,83 . Besides, the achieved RC eff is also comparable to those rare-earth containing La(FeSi) 13 -based 72,73 and Gd 5 (SiGe) 4 -based 74,75 compounds. Of note is that the working temperature of the present alloy is slightly above 300 K, which is very encouraging for room-temperature magnetic refrigeration applications.

Figure 8Effective magnetic refrigeration capacity RC eff and working temperature span under a magnetic field of 5.0 T for the present Co6 alloy and some most studied magnetocaloric materials, such as La(FeSi) 13 -based 72,73 , Gd 5 (SiGe) 4 -based 74,75 , NiMn-based 1,18,45,63,76–84 compounds.

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“…Besides, the achieved RC eff is also comparable to those rare-earth containing La(FeSi) 13 -based 72,73 and Gd 5 (SiGe) 4 -based 74,75 compounds. Of note is that the working temperature of the present alloy is slightly above 300 K, which is very encouraging for room-temperature magnetic refrigeration applications.

Figure 8Effective magnetic refrigeration capacity RC eff and working temperature span under a magnetic field of 5.0 T for the present Co6 alloy and some most studied magnetocaloric materials, such as La(FeSi) 13 -based 72,73 , Gd 5 (SiGe) 4 -based 74,75 , NiMn-based 1,18,45,63,76–84 compounds. These alloys were selected because their magnetocaloric effects (MCE) are all related to the first-order martensite transformation and are tested around the magnetostructural transition temperatures.

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Optimization of magnetocaloric properties of arc-melted and spark plasma-sintered LaFe11.6Si1.4

“…Recently, the origin of the spike has been attributed to the superheating of the FM state due to the magnetocaloric effect [20] or the alignment of magnetic domains [21]. DS M spikes have been observed in many materials such as MnAs [22] [17,25], La 1-x Pr xFe 11.5 Si 1.5 [26], and Mn 3 GaC [27]. The appearance of the spike is due to the incorrect application of the Maxwell relation.…”

“…The usual determination of DS M using magnetization data does not take into account magnetic irreversibility and usually results in erroneous spikes in the DS M estimations [16][17][18][19]. Recently, the origin of the spike has been attributed to the superheating of the FM state due to the magnetocaloric effect [20] or the alignment of magnetic domains [21].…”

Synthesis and characterization of [Cu(SiF6)(4,4′-bpy)2] with its H2 and CO2 adsorption

“…Compared to ZIF-8 and Cu(dhbc) 2 (4,4-bpy), the material is a good absorbent to capture CO 2 under the same conditions. According to Clausius-Clapeyron [35][36][37], the adsorption heat of CO 2 on the sample was calculated to be 22.18 KJ mol À1 , higher than ZIF-8 (15.93 kJ mol À1 ) [38].…”