TiFe₂Mnx: New Nonstoichiometric Laves Compounds with Rich Magnetic Properties

The Laves phases, a family of AB2-type intermetallic compounds, have attracted considerable attention in the fields of solid state chemistry and materials science. In this study, we synthesized a series of over-stoichiometric hexagonal Laves TiFe2Mnx (0 ≤ x ≤ 1.0) compounds using a supercritical quenching method, specifically by quenching from a high-temperature near melting point (Tm). Neutron powder diffraction (NPD) studies reveal that the excess Mn atoms occupy both the Ti and Fe sites. Magnetic measurement demonstrates that these compounds display multiple magnetic states ranging from antiferromagnetic order (x = 0), mixed antiferromagnetic–ferromagnetic order (x ≤ 0.3), to pure ferromagnetic order (0.3 < x < 0.4). Interestingly, a spin glass state emerges in the Mn-rich region (0.4 ≤ x ≤ 1.0) below the frozen temperature. A detailed analysis using NPD, ac magnetic susceptibility, and isothermal remanent magnetization (IRM) relaxation measurements demonstrated that spin glass may originate from magnetic frustration interaction among the Mn moment in the A-layer and Mn/Fe moment at the B layer (Kagome layer). Our work broadens the pathway for synthesizing new magnetic functional materials in nonstoichiometric compounds.