Anomalous spin fluctuations new the Molt transition in manganites

利用中子衍射技术系统地研究了空穴掺杂锰酸盐体系的晶体和磁性结构与空穴浓度的依赖关系，并确定了它们的相图。对自旋动力学的研究进一步揭示了自旋涨落在电荷有序转变温度及其附近由铁磁相关转变为反铁磁相关。我们发现ce型电荷/自旋有序态的自旋有序不是真正的长距离有序。轨道自由度产生了两个轨道有序模式域，并降低了ce型有序的自旋相关。

The hole concentration dependence of the crystal and magnetic structures of the hole doped manganite systems have been studied systematically with use of neutron diffraction technique, and their phase diagrams have been determined. The studies on the spin dynamics further revealed that the spin fluctuation changes its nature from ferromagnetic correlations to antiferromagnetic correlations at and near the charge ordering transition temperature. We discovered that the spin ordering in the CE-type charge/spin ordered state is not a true long range order. The orbital degree of freedom gives rise to two domains of orbital ordering patterns, and reduces the spin correlation, in the CE-type order.