Muñoz A, Alonso J A, Martínez-Lope M J, Falcón H, García-Hernández M, Morán E
Dpto. de Física Aplicada, EPS, Universidad Carlos III, Avda. Universidad 30, E-28911, Leganés-Madrid, Spain.
Dalton Trans. 2006 Nov 7(41):4936-43. doi: 10.1039/b607905a. Epub 2006 Aug 30.
We describe the preparation of SeMO(3) (M = Ni, Mn) under high pressure conditions (3.5 GPa), starting from reactive H(2)SeO(3) and MO mixtures, contained in sealed gold capsules under the reaction conditions 850 degrees C for 1 h. The polycrystalline samples have been studied by neutron powder diffraction (NPD) data and magnetization measurements. SeMO(3) (M = Ni, Mn) are orthorhombically distorted perovskites (space group Pnma). Below T(N) approximately 104 K (M = Ni) and T(N) approximately 53.5 K (M = Mn) these oxides experience an antiferromagnetic ordering, as demonstrated by susceptibility and NPD measurements. The magnetic reflections observed in the neutron patterns can be indexed with a propagation vector k = 0. Both compounds present the same magnetic structure, which is given by the basis vector (0, 0, A(z)). It can be described as antiferromagnetic (010) layers of magnetic moments lying along the c direction, which are antiferromagnetically coupled along the b direction. For the Ni(2+) ions, the ordered magnetic moment at T = 2.3 K is 2.11(3) micro(B), whereas for Mn(2+) at T = 2.6 K, |m| = 4.64(2) micro(B), consistent with the electronic configurations te (Ni(2+)) and te (Mn(2+)).
我们描述了在高压条件（3.5吉帕）下，由反应性的H₂SeO₃和MO混合物开始制备SeMO₃（M = Ni，Mn）的过程。这些混合物置于密封的金胶囊中，在850℃的反应条件下保持1小时。通过中子粉末衍射（NPD）数据和磁化测量对多晶样品进行了研究。SeMO₃（M = Ni，Mn）是正交畸变的钙钛矿（空间群Pnma）。低于Tₙ约104 K（M = Ni）和Tₙ约53.5 K（M = Mn）时，这些氧化物经历反铁磁有序化，这由磁化率和NPD测量所证实。在中子衍射图谱中观察到的磁反射可以用传播矢量k = 0来标定。两种化合物具有相同的磁结构，其由基矢(0, 0, A(z))给出。它可以描述为沿着c方向排列的磁矩的反铁磁(010)层，这些磁矩在b方向上反铁磁耦合。对于Ni²⁺离子，在T = 2.3 K时的有序磁矩为2.11(3) μB，而对于Mn²⁺在T = 2.6 K时，|m| = 4.64(2) μB，这与电子构型te（Ni²⁺）和te（Mn²⁺）一致。
