Crystal structure and magnetic properties of the 5d transition metal oxides AOsO(4)(A = K, Rb, Cs)

Article

关键词: 3-DIMENSIONAL VISUALIZATION;   

DOI  :  10.1103/PhysRevB.99.155113

来源: SCIE

【 摘 要 】

We synthesized the 5d(1) transition-metal oxides AOsO(4)(A = K, Rb, Cs) by solid-state reaction, and performed structure determination and magnetic and heat capacity measurements. It was found that they crystallize in a scheelite (A = K and Rb) or a quasischeelite structure (A = Cs) comprising distorted diamond lattices of septivalent Os (d(1)) ions tetrahedrally coordinated by four oxide ions without local inversion symmetry; hence an antisymmetric spin-orbit coupling is expected in the crystals. The K and Rb compounds haveWeiss temperatures of theta = -66 and -18K, effective magnetic moments of mu(eff) = 1.44 and 1.45 mu(B)/Os, and antiferromagnetic transition temperatures of T-N = 36.9 and 21.0 K, respectively. In contrast, the Cs compound has theta = 12K and mu eff = 0.8 mu(B)/Os without magnetic transition above 2 K, instead exhibiting a first-order structural transition at T-s = 152.5K. The decline of the Os moment from 1.73 mu(B)/Os for the simple d(1) spin, particularly for Cs, is likely to originate from the antiparallel orbital moment, although the spin-orbit coupling is generally quenched in the low-lying e orbitals.

【 授权许可】

Free