Abstract Magnetic and neutron powder diffraction measurements have been carried out on Tb0.9Er0.1Ni5 intermetallic compound. The intermetallide crystallizes in the hexagonal CaCu5-type structure and possesses a long-range magnetic order at temperatures below 22 K. A fan-like magnetic structure is described by two propagation vectors: k1 = 0 and k2 = 2π/c(0, 0, 0.036), at 20 K. The total Tb-ion magnetic moment has the ferromagnetic and modulated components. The latter is a transverse spin wave. When the sample is cooled at a temperature below 8 K, the module of the k2 vector does not change and is equal to k2 = 2π/c(0, 0, 0.027). An “incommensurate – lock-in” magnetic transition takes place at 8 K. The k2 vector exhibits a temperature hysteresis of about (5–6) K, whereas the intensities of Bragg reflections and satellites do not show up appreciable changes. When an external magnetic field is applied to the sample, the satellites and the module of the k2 vector decrease, while the Bragg intensities increase. The sample becomes a ferromagnetic at a field of ∼2 kOe, and the Tb-ion magnetic moment is equal to 8.3 μB. A general notion of the Tb0.9Er0.1Ni5 magnetic state evolution with an external field is given using the field dependence of the background intensity in diffraction patterns. First principle calculations for TbNi5 and Tb0.9Er0.1Ni5 are performed including the 4f states into the orbital basis and accounting for strong electronic correlations and spin-orbital coupling. This allowed obtaining both spin and orbital moments of the effective Tb-ion moment and estimating also the value of Tb-Tb exchange interaction.

中文翻译：

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Tb0.9Er0.1Ni5 中的自发和感应磁相变

摘要 对Tb0.9Er0.1Ni5金属间化合物进行了磁衍射和中子粉末衍射测量。金属间化合物在六方 CaCu5 型结构中结晶，并在低于 22 K 的温度下具有长程磁序。扇状磁结构由两个传播向量描述：k1 = 0 和 k2 = 2π/c(0, 0 , 0.036), 在 20 K。总 Tb 离子磁矩具有铁磁和调制分量。后者是横向自旋波。当样品在低于 8 K 的温度下冷却时，k2 矢量的模数不变，等于 k2 = 2π/c(0, 0, 0.027)。在 8 K 处发生“不公度锁定”磁转变。 k2 矢量表现出大约 (5–6) K 的温度滞后，而布拉格反射和卫星的强度没有显示出明显的变化。当对样品施加外部磁场时，卫星和 k2 矢量的模数减少，而布拉格强度增加。样品在 ∼2 kOe 的磁场下变成铁磁体，Tb 离子磁矩等于 8.3 μB。Tb0.9Er0.1Ni5 磁态随外场演化的一般概念是使用衍射图案中背景强度的场依赖性给出的。执行 TbNi5 和 Tb0.9Er0.1Ni5 的第一原理计算，将 4f 态纳入轨道基础并考虑强电子相关性和自旋轨道耦合。