量子自旋液體(QSL)候選材料研究中具有潛在的應用而備受關注，被視為實現拓撲量子計算的重要平台，其中由Alexei Kitaev所提出的Kitaev model對QSL在二維蜂巢晶格下的精確解，並且預測了Majorana fermion的存在。儘管在4d/5d過渡金屬化合物中已觀察到Kitaev交互作用的跡象，但其長程磁序阻礙了QSL的實現。近期研究指出，3d7組態的Co2+離子可形成自旋-軌道糾纏的Jeff = 1/2偽自旋態，為實現Kitaev交互作用提供了新途徑。
本研究以銅鐵礦(Delafossite)衍生物Cu3M2SbO6 (M = Co, Ni, Mn)為對象，該系列材料皆由MO6八面體構成的二維蜂巢層狀結構。以X光繞射與X光光電子能譜確認其結構與價態。磁性與熱性量測顯示三種材料在低溫下皆出現反鐵磁相變，發現Cu3Co2SbO6 (CCSO)在相變溫度以下表現出複雜的熱力學特徵。
針對至今尚未研究磁性結構的Cu3Mn2SbO6 (CMSO)進行中子粉末繞射解析，將其磁結構與Cu3Co2SbO6 (CCSO)和Cu3Ni2SbO6 (CNSO)進行比較。而非彈性中子散射(INS)為本研究的核心，從CCSO的INS光譜中觀測到約21 meV的自旋-軌道激子，證實了具有Jeff = 1/2偽自旋基態。透過SpinW擬合CCSO的激發光譜，揭示其具有FM Kitaev交互作用（K = -1.683 meV）為主導，且K/J1 = 1.319，使其成為接近Kitaev QSL的材料。而藉由非S = 1/2基態的CNSO和CMSO的比較，可以值觀地探討Kitaev交互作用與傳統自旋間交互作用的競爭，以及對磁結構的影響。

Two-dimensional honeycomb magnets are promising platforms for Kitaev QSL. This study systematically investigates the magnetic properties of delafossite-type Cu3M2SbO6 (M = Co, Ni, Mn) polycrystalline powders. Through XRD and XPS, we confirmed the crystal structures and valence states of the transition metal ions. Magnetic susceptibility and specific heat measurements reveal antiferromagnetic transitions at low temperatures, with Cu3Co2SbO6 (CCSO) exhibiting complex thermodynamic behavior below the tran-sition temperature. Neutron powder diffraction (NPD) resolved the magnetic structure of Cu3Mn2SbO6 (CMSO) for the first time. The core of this study is inelastic neutron scat-tering (INS). For CCSO, a spin-orbit exciton at ~21 meV was observed, confirming the Jeff = 1/2 pseudospin ground state. SpinW fitting of CCSO reveals a dominant ferromag-netic Kitaev interaction (K = -1.683 meV), with K/J1 = 1.319, positioning it as a proxi-mate Kitaev QSL material. By comparing non-S = 1/2 CNSO and CMSO, we discuss the competition between Kitaev and conventional spins, alongside their effects on magnetic structures.

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