Exchange bias effect on Fe-excess Fe1.1Te crystals

Exchange bias (EB) is characterized by a horizontal shift in magnetic hysteresis loops, originating from interfacial coupling between ferromagnetic (FM) and antiferromagnetic (AFM) layers. This phenomenon enables key regulation of magnetic coercivity and spin alignment in spintronic devices. Conventionally engineered in FM/AFM heterostructures. We report exchange bias (EB) in self-flux-grown Fe₁.₁Te single crystals, where Fe excess drives stoichiometric deviation. Structural analysis confirms a tetragonal FeTe phase with no secondary phases, while magnetic measurements reveal coexistence of ferromagnetic (FM) behavior (from excess Fe) and intrinsic antiferromagnetism (AFM) of FeTe. This is evidenced by a zero-field-cooled/field-cooled magnetization bifurcation below the Néel temperature ( T N  ≈ 65 K). H EB decays linearly with temperature (vanishing near T N ) and scales with the magnitude of the cooling field. We attribute EB to interfacial coupling between FM clusters (Fe-rich) and the AFM FeTe matrix. This work establishes Fe₁.₁Te as a tunable platform for antiferromagnetic spintronics, leveraging stoichiometric control to engineer interfacial magnetic coupling.