论文标题
重新访问多效Knipo的磁性和晶体结构$ _4 $
Revisiting the magnetic and crystal structure of multiferroic KNiPO$_4$
论文作者
论文摘要
已经通过中子粉末衍射，磁化，介电和高温同步子XRD测量来研究了I型多能Knipo $ _4 $的磁，介电和结构特性。在$ t_ \ mathrm {n} $ = 25 k的néel转变下方，knipo $ _4 $显示出一个弱的非电线反铁磁性（AFM）结构，其方向是Ni $^{2+} $磁矩，主要沿$ AXIS沿$ Axis。该复合物在室温下在极性正交$ PNA2_1 $空间群中结晶。在$ t_ \ mathrm {c} \ sim $ 594（3）$^\ circ $ c上观察到对应于发作铁电的二阶结构相变，高于nipo $ _4 $的晶体结构，采用Centrosmmetric $ PNMA $ Space Group。该化合物还以$ t_ \ mathrm {0} \ sim $ 469-488 $^\ circ $ c的形式显示另一种结构相变，带有一阶特征，这归因于氧配体的重排，从而使镍离子离子的变化从四个到五。
The magnetic, dielectric and structural properties of type-I multiferroic KNiPO$_4$ have been investigated by neutron powder diffraction, magnetization, dielectric and high temperature synchrotron-XRD measurements. Below the Néel transition of $T_\mathrm{N}$ = 25 K, KNiPO$_4$ displays a weakly non-collinear antiferromagnetic (AFM) structure with the orientation of the Ni$^{2+}$ magnetic moments mainly along $a$ axis. The compound crystallizes in the polar orthorhombic $Pna2_1$ space group at room temperature. A second-order structural phase transition corresponding to the onset ferroelectricity is observed at around $T_\mathrm{C}\sim$ 594(3)$^\circ$C, above which the crystal structure of KNiPO$_4$ adopts the centrosymmetric $Pnma$ space group. The compound also displays another structural phase transition at $T_\mathrm{0}\sim$ 469 -- 488$^\circ$C, with a first-order character, which is attributed to the rearrangement of oxygen ligands, resulting in a change in the nickel ion co-ordination from four to five.
