Orbital character of the spin-reorientation transition in TbMn$_6$Sn$_6$
S. X. M. Riberolles, Tyler J. Slade, R. L. Dally, P. M. Sarte, Bing Li, Tianxiong Han, H. Lane, C. Stock, H. Bhandari, N. J. Ghimire, D. L. Abernathy, P. C. Can… 展开作者
S. X. M. Riberolles, Tyler J. Slade, R. L. Dally, P. M. Sarte, Bing Li, Tianxiong Han, H. Lane, C. Stock, H. Bhandari, N. J. Ghimire, D. L. Abernathy, P. C. Canfield, J. W. Lynn, B. G. Ueland, R. J. McQueeney
Ferromagnetic (FM) order in a two-dimensional kagome layer is predicted to generate a topological Chern insulator without an applied magnetic field. The Chern gap is largest when spin moments point perpendicular to the kagome layer, enabling the capability to switch topological transport properties, such as the quantum anomalous Hall effect, by controlling the spin orientation. In TbMn$_{6}$Sn$_{6}$, the uniaxial magnetic anisotropy of the Tb$^{3+}$ ion is effective at generating the Chern state within the FM Mn kagome layers while a spin-reorientation (SR) transition to easy-plane order above $T_{SR}=310$ K provides a mechanism for switching. Here, we use inelastic neutron scattering to provide key insights into the fundamental nature of the SR transition. The observation of two Tb excitations, which are split by the magnetic anisotropy energy, indicates an effective two-state orbital character for the Tb ion, with a uniaxial ground state and an isotropic excited state. The simultaneous observation of both modes below $T_{SR}$ confirms that orbital fluctuations are slow on magnetic and electronic time scales $<$ ps and act as a spatially-random orbital alloy. A thermally-driven critical concentration of isotropic Tb ions triggers the SR transition.
Magnetically induced electric polarization reversal in multiferroic TbMn$_2$O$_5$: Terbium spin reorientation studied by resonant x-ray diffraction
在多铁性TbMn $_2$ O $_5$中，铽离子的行为形成磁电耦合的关键部分。结果是在2 T下磁感应电极化的强度反转。在这篇文章中，我们提出了在外加磁场下的铽磁性结构的第一个直接测量。与目前对\tmo磁性的解释相反，我们表明，在电极化的强度反转时，铽子晶格采用倾斜的反铁磁结构，具有平行于\textit{a}轴的磁矩的大分量。此外，我们提供的证据之间的耦合锰的3D磁性结构和铽$4f$磁性，这是在难以捉摸的磁电机制发挥重要的意义。
Anisotropic mesoscale magnetic scattering across the spin-reorientation transition in TbMn6Sn6
Spallation Neutron Source Science Center（散裂中子源科学中心）；Institute of High Energy Physics, Chinese Academy of Sciences (CAS)（中国科学院高能物理研究所）；Guangdong Provincial Key Laboratory of Extreme Conditions（广东省极端条件重点实验室）
First-Order Spin-Reorientation Transition and Incomplete Softening of the Antiferromagnetic Resonance Mode in Multiferroic GdFe$_3$(BO$_3$)$_4$
Kirensky Institute of Physics, Krasnoyarsk Scientific Center, Siberian Branch, Russian Academy of Sciences（俄罗斯科学院西伯利亚分院克拉斯诺亚尔斯克科学中心基连斯基物理研究所）；Siberian Federal University（西伯利亚联邦大学）
Spin Reorientation Driven Renormalization of Spin-Phonon Coupling in Fe$_4$GeTe$_2$
S. N. Bose National Centre for Basic Sciences（S.N. 玻色基础科学国家中心）；Uppsala University（乌普萨拉大学）；Bose Institute（玻色研究所）；Indian Institute of Technology Madras（马德拉斯印度理工学院）；Saha Institute of Nuclear Physics（萨哈核物理研究所）
Probing magnetic anisotropy and spin-reorientation transition in 3D antiferromagnet, Ho$_{0.5}$Dy$_{0.5}$FeO$_{3}\vert$Pt using spin Hall magnetoresistance
Strong Spin Resonance Mode associated with suppression of soft magnetic ordering in Hole-doped Ba1-xNaxFe2As2
自旋共振模（SRM）被认为是铁基超导体中磁驱动配对的证据，但其性质仍然知之甚少。SRMs的宽度、分裂和自旋空间各向异性与大多数被接受的自旋激子解释相反。我们研究了空穴掺杂Ba $_{1-x}$ Na $_x$ Fe $_2$ As $_2$的自旋重取向转变。这种重新取向对具有高能量各向同性和低能量各向异性模式的共振激发的整体外观几乎没有影响。然而，各向异性低能模式的强度在最高掺杂处急剧达到峰值，该最高掺杂仍然表现出磁有序，从而导致迄今为止在任何Fe基超导体中观察到的最强SRM。这种非常强的SRM伴随着进入SC相时约一半的磁布拉格强度的损失。因此，各向异性SRM可以允许系统补偿由SC状态内的降低的反铁磁相关性引起的交换能量的损失。
Spin Canting and Orbital Order in Spinel Vanadate Thin Films
我们报道了CoV $_2$ O $_4$的外延薄膜生长和表征，这是一种近巡回尖晶石钒酸盐，生长在（001）SrTiO $_3$上。的对称性降低的晶胞从立方的散装正交的薄膜相比，散装的磁各向异性的结果在显着的差异，从结构和磁性表征确定。大块立方CoV $_2$ O $_4$与预测不符，轨道简并似乎持续到非常低的温度，在磁化和中子实验中只有小的异常，表明T = 90 K时可能发生自旋/轨道玻璃化转变。在本文提出的外延薄膜中，结构上将CoV $_2$ O $_4$从立方对称性中调谐出来导致完全不同的低温非共线基态。通过磁化和中子散射测量，我们表明，90 K的转变是与一个主要的自旋重取向远离亚铁磁易轴[001]的[110]方向。此外，V-自旋倾斜远离该方向，提取的垂直力矩提供了与体积相比更大的倾斜角的证据。该结果表明，压缩应变将系统更深地推入绝缘状态，即，远离本地-流动的交叉制度。
