A core–shell magnet Mn70Bi30 grown at seeds in magnetic fields and its impacts on its spin-dynamics, Curie point and other tailored properties

• DOI: 10.1088/1361-6528/acd34c
• Publication Date: 2023-05-08T22:21:00Z
• Authors: Sanjeev Kumar Sharma; Debabrata Pradhan; Shanker Ram
• Keywords: Magnetocrystalline anisotropy

The MnBi alloys is a model series of rare-Earth free magnets for surge technologies small parts automobiles, power generators, medical tools, memory systems, and many others. magnetics stem primarily at unpaired Mn-3d5spins (a 4.23μBmoment) align parallel via an orbital moment 0.27μBof Bi-5d106s2p3in crystal lattice. Thus, using surplus Mn (over Bi) in Mn70Bi30type alloy designs spin-rich system duly tailored properties useful other devices. In this view, we report here strategy refined powder Mn70Bi30can grow into crystals hexagonal (h) plates seeds as annealed magnetic fields (in H2gas). So, h-plates (30 to 50 nm widths) are grown up (002) facets, wherein the edges turned down spiral (≤2.1 thicknesses) core-shell structure. results described with x-ray diffraction, lattice images Mn70Bi30(milled glycine) 573 K different time periods, so Mn/Bi order permeable facets (seeds). Duly samples exhibit enhanced magnetization,Ms→ 70.8 emu g-1, promoted coercivityHc→ 10.810 kOe (15.910 350 K), energy-product 14.8 MGOe, crystal-field-anisotropy,K1→ 7.6 × 107erg cm-3, reported room temperature. Otherwise,Msshould decline any 3d5-Mn spins antiparallel antisites. Enhanced Curie point 658.1 (628 Mn50Bi50alloy) anticipates that does favor Mn-Bi exchange interactions. Proposed spin models well describe spin-dynamics relaxations (on anneals) over volume (with twins) clusters.