We report a linear dependence of the phonon splitting \Delta\omega on the non-dominant exchange coupling constant J_{nd} in the antiferromagnetic transition-metal monoxides MnO, FeO, CoO, NiO, and in the frustrated antiferromagnetic oxide spinels CdCr2O4, MgCr2O4, and ZnCr2O4. It directly confirms the theoretical prediction of an exchange induced splitting of the zone-centre optical phonon for the monoxides and explains the magnitude and the change of sign of the phonon splitting on changing the sign of the non-dominant exchange also in the frustrated oxide spinels. The experimentally found linear relation \hbar\Delta\omega = \beta J_{nd} S^2 with slope \beta = 3.7 describes the splitting for both systems and agrees with the observations in the antiferromagnets KCoF3 and KNiF3 with perovskite structure and negligible next-nearest neighbour coupling. The common behavior found for very different classes of cubic antiferromagnets suggests a universal dependence of the exchange-induced phonon splitting at the antiferromagnetic transition on the non-dominant exchange coupling.
翻译:我们报告,在抗冻性磁性过渡-海洋氧化物MnO、FeO、COO、NiO中,在阻力的抗腐蚀性氧化物脊椎CdCr2O4、MgCr2O4和ZnCr2O4中,磷分解线线依赖非支配性交换常数J ⁇ (J ⁇ nd),这直接证实了在理论上预测一氧化物区中心光学光学圆柱的分解,并解释了在改变非支配性过渡-海洋氧化物MnO、FO、COO、NiO中,以及在沮丧的氧化物脊髓脊髓脊椎脊椎脊椎脊椎脊脊脊椎脊椎脊椎脊椎脊椎脊椎脊椎脊椎中,在改变非支配性过渡性交流的分解迹象和变化迹象。实验发现,与斜度=beta=3.7的斜度S&2的线性关系说明了两种系统的分解,并赞同在反纤维磁网 KCOF3和KiF3中观察到的反腐蚀结构结构和可忽略的次次次的互换式互换式底邻国的互换式互换式互判。