β‑Mn-Type Co8+xZn12–x as a Defect Cubic Laves Phase: Site Preferences, Magnetism, and Electronic Structure

The results of crystallographic analysis, magnetic characterization, and theoretical assessment of β-Mn-type Co–Zn intermetallics prepared using high-temperature methods are presented. These β-Mn Co–Zn phases crystallize in the space group P4132 [Pearson symbol cP20; a = 6.3555(7)–6.3220(7)], and their stoichiometry may be expressed as Co8+xZn12–x [1.7(2) x 8+xZn12–x reveals that the β-Mn aristotype may be derived from an ordered defect, cubic Laves phase (MgCu2-type) structure. Structural optimization procedures using the Vienna ab initio simulation package (VASP) and starting from the undistorted, defect Laves phase structure achieved energy minimization at the observed β-Mn structure type, a result that offers greater insight into the β-Mn structure type and establishes a closer relationship with the corresponding α-Mn structure (cI58).