本篇論文主要是因為我們對Na3Cu2SbO6的自旋能隙行為感到有興趣，於是我們將樣品粉末從4 K到300 K做了23Na核磁共振量測，利用核磁共振量測來觀察樣品的磁特性。我們對Na3Cu2SbO6進行23Na核磁共振研究，其中分奈特位移和自旋晶格鬆弛率兩部分來詳述此樣品之磁特性。在與溫度相關的NMR shift中發現，樣品具有低維磁特性，且在Tmax=95 K有段很寬的最大值，而低於95 K時NMR shift則急速下降。在溫度小於Tmax時，NMR shift和自旋晶格鬆弛率皆明顯有活性反應，證實了在本樣品Na3Cu2SbO6確實具有自旋能隙。從實驗得到的NMR數據，發現反鐵磁-反鐵磁交替鏈模型(AF-AF alternating chain model)和反鐵磁-鐵磁交替鏈模型(AF-F alternating chain model)皆適用於擬合本實驗之NMR數據，其中前者可得到一自旋能隙約為62 K，而這值與由中子散射測量所得到的能隙104 K (8.9 meV)相比小了許多。而由後者所得到的自旋能隙約為112 K，與8.9 meV相差不多。這也說明AF-F交替鏈模型較適合用來了解Na3Cu2SbO6之自旋能隙性質。

We report the results of a 23Na nuclear magnetic resonance (NMR) study on Na3Cu2SbO6 at temperatures between 4 and 300 K, due to interested in spin gap behavior of Na3Cu2SbO6. We will present a detailed 23Na nuclear magnetic resonance study invoking NMR shift and spin lattice relaxation rates on this compound. The temperature-dependent NMR shift exhibits a character of low-dimensional magnetism with a broad maximum at Tmax≃95 K, the NMR shift decreases rapidly with lowering temperature. Below Tmax, the NMR shift and spin lattice relaxation rates clearly indicate activated responses, confirming the existence of a spin gap in Na3Cu2SbO6. The experimental NMR data can be well fitted to the AF-AF alternating chain model and AF-F alternating chain model, the former yields a spin gap of about 62 K which is substantially smaller than 104 K (8.9 meV) observed by the neutron scattering measurement. The latter yields a spin gap of about 112 K, close to the 8.9 meV. It thus points out that the AF-F alternating chain model is proper for the understanding of the spin gap nature in Na3Cu2SbO6.
 

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