TY - JOUR
T1 - Magnetocaloric effect in the (Mn,Fe)2(P,Si) system
T2 - From bulk to nano
AU - Zhang, Fengqi
AU - Taake, Chris
AU - Huang, Bowei
AU - You, Xinmin
AU - Ojiyed, Hamutu
AU - Shen, Qi
AU - Dugulan, Iulian
AU - Caron, Luana
AU - van Dijk, Niels
AU - Brück, Ekkes
PY - 2022
Y1 - 2022
N2 - In the field of nanoscale magnetocaloric materials, novel concepts like micro-refrigerators, thermal switches, microfluidic pumps, energy harvesting devices and biomedical applications have been proposed. However, reports on nanoscale (Mn,Fe)2(P,Si)-based materials, which are one of the most promising bulk materials for solid-state magnetic refrigeration, are rare. In this study we have synthesized (Mn,Fe)2(P,Si)-based nanoparticles, and systematically investigated the influence of crystallite size and microstructure on the giant magnetocaloric effect. The results show that the decreased saturation magnetization (Ms) is mainly attributed to the increased concentration of an atomically disordered shell, and with a decreased particle size, both the thermal hysteresis and Tc are reduced. In addition, we determined an optimal temperature window for annealing after synthesis of 300–600 °C and found that gaseous nitriding can enhance Ms from 120 to 148 Am2kg−1 and the magnetic entropy change (ΔSm) from 0.8 to 1.2 Jkg−1K−1 in a field change of Δμ0H = 1 T. This improvement can be attributed to the synergetic effect of annealing and nitration, which effectively removes part of the defects inside the particles. The produced superparamagnetic particles have been probed by high-resolution transmission electron microscopy, Mössbauer spectra and magnetic measurements. Our results provide important insight into the performance of giant magnetocaloric materials at the nanoscale.
AB - In the field of nanoscale magnetocaloric materials, novel concepts like micro-refrigerators, thermal switches, microfluidic pumps, energy harvesting devices and biomedical applications have been proposed. However, reports on nanoscale (Mn,Fe)2(P,Si)-based materials, which are one of the most promising bulk materials for solid-state magnetic refrigeration, are rare. In this study we have synthesized (Mn,Fe)2(P,Si)-based nanoparticles, and systematically investigated the influence of crystallite size and microstructure on the giant magnetocaloric effect. The results show that the decreased saturation magnetization (Ms) is mainly attributed to the increased concentration of an atomically disordered shell, and with a decreased particle size, both the thermal hysteresis and Tc are reduced. In addition, we determined an optimal temperature window for annealing after synthesis of 300–600 °C and found that gaseous nitriding can enhance Ms from 120 to 148 Am2kg−1 and the magnetic entropy change (ΔSm) from 0.8 to 1.2 Jkg−1K−1 in a field change of Δμ0H = 1 T. This improvement can be attributed to the synergetic effect of annealing and nitration, which effectively removes part of the defects inside the particles. The produced superparamagnetic particles have been probed by high-resolution transmission electron microscopy, Mössbauer spectra and magnetic measurements. Our results provide important insight into the performance of giant magnetocaloric materials at the nanoscale.
KW - (Mn,Fe)2(P,Si)
KW - Magnetization
KW - Magnetocaloric materials
KW - Nanoparticles
KW - Phase transition
UR - http://www.scopus.com/inward/record.url?scp=85120939632&partnerID=8YFLogxK
U2 - 10.1016/j.actamat.2021.117532
DO - 10.1016/j.actamat.2021.117532
M3 - Article
AN - SCOPUS:85120939632
VL - 224
JO - Acta Materialia
JF - Acta Materialia
SN - 1359-6454
M1 - 117532
ER -