Pb2MnTeO6 Double Perovskite: An Antipolar Anti-ferromagnet.
Pb2MnTeO6 Double Perovskite: An Antipolar Anti-ferromagnet.
复制标题
Pb2MnTeO6 双钙钛矿：一种反极性反铁磁体。
作者：
M. Retuerto;Stella Skiadopoulou;Manrong Li;A. Abakumov;M. Croft;A. Ignatov;T. Sarkar;Brian M. Abbett;J. Pokorny;M. Savinov;D. Nuzhnyy;J. Prokleška;M. Abeykoon;P. Stephens;J. P. Hodges;P. Vanĕk;C. Fennie;K. Rabe;S. Kamba;M. Greenblatt
合成了一种新型双钙钛矿结构Pb_2MnTeO_6。用同步辐射X射线衍射和粉末中子衍射测定了它的晶体结构。Pb 2 MnTeO 6在室温下是单斜晶系（I2/m），所有阳离子在其多面体中规则排列。然而，当温度降低到120 K时，它经历了从I2/m到C2/c结构的相变。这种转变伴随着由于6s（2）孤对电子导致的Pb原子从其多面体中心的位移，以及Mn（2+）（d（5））磁性阳离子的令人惊讶的偏心。这种强的一级相变也证明了比热，介电，拉曼，红外光谱测量。磁性表征表明，反铁磁（AFM）的顺序低于TN <$20 K;粉末中子衍射数据的分析证实了传播矢量k =（0 1 0）和共线AFM自旋的磁结构。所观察到的介电常数在150 K附近的跳跃意味着可能的反铁电行为;然而，没有开关表明Pb 2 MnTeO 6只能是反极性的。第一性原理计算证实，确定的晶体和磁性结构是局部稳定的，并且在Pb 2 MnTeO 6中不太可能观察到反铁电开关。
Pb2MnTeO6, a new double perovskite, was synthesized. Its crystal structure was determined by synchrotron X-ray and powder neutron diffraction. Pb2MnTeO6 is monoclinic (I2/m) at room temperature with a regular arrangement of all the cations in their polyhedra. However, when the temperature is lowered to ∼120 K it undergoes a phase transition from I2/m to C2/c structure. This transition is accompanied by a displacement of the Pb atoms from the center of their polyhedra due to the 6s(2) lone-pair electrons, together with a surprising off-centering of Mn(2+) (d(5)) magnetic cations. This strong first-order phase transition is also evidenced by specific heat, dielectric, Raman, and infrared spectroscopy measurements. The magnetic characterizations indicate an anti-ferromagnetic (AFM) order below TN ≈ 20 K; analysis of powder neutron diffraction data confirms the magnetic structure with propagation vector k = (0 1 0) and collinear AFM spins. The observed jump in dielectric permittivity near ∼150 K implies possible anti-ferroelectric behavior; however, the absence of switching suggests that Pb2MnTeO6 can only be antipolar. First-principle calculations confirmed that the crystal and magnetic structures determined are locally stable and that anti-ferroelectric switching is unlikely to be observed in Pb2MnTeO6.
影响因子：
15
作者：
Morrow, Ryan;Mishra, Rohan;Woodward, Patrick M.
通讯作者：
Woodward, Patrick M.