Roadmap towards optimal magnetic properties in L10-MnAl permanent magnets

Rare‐Earth‐Free Mn30Fe20−xCuxAl50 Magnetocaloric Materials with Stable Cubic CsCl‐Type Structure for Room‐Temperature Refrigeration

“…The MnAl-based alloy family has aroused some research interests in recent years due to their inherent magnetic performance and low cost of raw materials. [17][18][19][20][21][22][23][24][25][26] They have been considered a potential candidate system for replacing the well-known RE-based permanent magnets. The prominent magnetic properties of MnAl-based alloys mainly originate from ferromagnetic 𝜏-phase MnAl with a Curie temperature (T C ) of 650 K, which crystallizes in a body-centered tetragonal L10 structure (space group: P4/mmm).…”

“…The 𝜏-phase is easily decomposed into the nonmagnetic Al 8 Mn 5 (space group: R3m) and the 𝛽-Mn (space group: P 4 132) phases at elevated temperatures. [24][25][26] Numerous attempts have been made to obtain the high-T C ferromagnetic 𝜏-phase and optimize the hard magnetic performances using element substitutions, heat treatment, microstructure refinement, and defect engineering. [21][22][23][24][25][26] In short, the MnAl-based alloys have relative rich known phases and tunable structural and magnetic properties as well as large theoretical saturation magnetic moment limitation.…”

“…[24][25][26] Numerous attempts have been made to obtain the high-T C ferromagnetic 𝜏-phase and optimize the hard magnetic performances using element substitutions, heat treatment, microstructure refinement, and defect engineering. [21][22][23][24][25][26] In short, the MnAl-based alloys have relative rich known phases and tunable structural and magnetic properties as well as large theoretical saturation magnetic moment limitation. [19][20][21][22] Thus, MnAl-based alloys should have the potentiality to be a new family of prominent magnetocaloric materials if their magnetic phase transition (MPT) temperature can be tuned to ideal temperatures with a magnetically soft and large moment.…”

“…[ 24–26 ] Numerous attempts have been made to obtain the high‐ T C ferromagnetic τ‐phase and optimize the hard magnetic performances using element substitutions, heat treatment, microstructure refinement, and defect engineering. [ 21–26 ]…”

“…The τ‐phase is easily decomposed into the nonmagnetic Al 8 Mn 5 (space group: R 3 m ) and the β‐Mn (space group: P 4 132) phases at elevated temperatures. [ 24–26 ] Numerous attempts have been made to obtain the high‐ T C ferromagnetic τ‐phase and optimize the hard magnetic performances using element substitutions, heat treatment, microstructure refinement, and defect engineering. [ 21–26 ]…”