论文标题
群集玻璃的过渡和放松在随机尖晶石COGA2O4中
Cluster glass transition and relaxation in random spinel CoGa2O4
论文作者
论文摘要
我们报告了随机尖晶石磁铁COGA2O4中的磁性特性。 COGA2O4的X射线衍射曲线的Rietveld分析表明，CO和GA离子在三色体A位点和八面体B-位置随机分布在三次尖晶石结构中。 COGA2O4在TSG = 8.2 K处表现出旋转玻璃的跃迁，这通过测量DC和AC-舒张性和热量磁化（TRM）的测量得到了证实，该磁力强化（TRM）在TSG以下发展。从COGA2O4的冷冻温度TF的频率依赖性，可以表明放松时间遵循Vogel-Fulcher定律。磁熵大大降低，可能是因为即使在TSG处也会发展出磁簇的形成。 TSG时TRM的松弛率大大提高，并且在TSG上方和下方迅速衰减。 TRM的时间过程是通过非指数弛豫形式复制的，例如拉伸指数（Kohlrausch）以及Ogielski和Weron弛豫形式。这种行为普遍显示在玻璃系统中，与这些功能相关的特征参数是合理的。
We report magnetic properties in the random spinel magnet CoGa2O4. Rietveld analysis of the x-ray diffraction profile for CoGa2O4 reveals that the Co and Ga ions are distributed randomly in the tetrahedral A-sites and octahedral B-sites in the cubic spinel structure. CoGa2O4 exhibits a spin-glass transition at TSG = 8.2 K that is confirmed by measurements of the dc- and ac-susceptibilities and thermoremanent magnetization (TRM) that develops below TSG. From the frequency dependence of the freezing temperature Tf for CoGa2O4, it is indicated that the relaxation time follows a Vogel-Fulcher law. Magnetic entropy is considerably reduced, probably because magnetic cluster formation developed even at T > TSG. The relaxation rate of TRM is considerably enhanced at TSG and decays rapidly above and below TSG. The time course of TRM is reproduced by non-exponential relaxation forms, such as a stretched exponential (Kohlrausch) as well as Ogielski and Weron relaxation forms. This behavior is displayed universally in glass systems, and the characteristic parameters associated with these functions were reasonable.
