Browsing by Author "Vasala, S"

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    Magnetic structure of Sr2CuWO6
    (IOP Science, 2014-11-12) Vasala, S; Avdeev, M; Danilkin, SA; Chmaissem, O; Karppinen, M
    Magnetic structure of the double perovskite Sr2CuWO6 was determined from neutron powder diffraction data. At 3K the material is magnetically long-range ordered into a collinear antiferromagnetic structure described by a propagation vector k = (0, 1/2, 1/2) with the CuII moments of 0.57(1) μB parallel to the a-axis. The result is in agreement with our previous prediction (Vasala et al 2014 Phys. Rev. B 89 134419) based on electronic structure calculations, showing that the three-dimensional magnetic long-range order is caused by relatively strong antiferromagnetic next-nearest-neighbor interactions.© 2014, IOP Publishing Ltd.
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    Properties of the low dimensional Sr2Cu(W1-xMox)O6 spin system
    (American Physical Society, 2015-03-06) Chmaissem, O; Avdeev, M; Danilkin, SA; Vasala, S; Yamauchi, H; Karppinen, M
    Low-dimensional spin systems have gained much attention in solid state physics. Such systems could have a ground state with no long-range magnetic order and an energy gap in the spin excitation spectrum, offering the possibility of a quantum spin-liquid phase. Quantum fluctuations causing the spin-liquid state are particularly strong in systems with reduced dimensionality and a low spin value; and magnetic frustration can further enhance the fluctuations. Among various low-dimensional spin systems, the S = 1/2 Heisenberg frustrated square lattice model is especially interesting due to its relevance to high-TC superconducting cuprates, whose undoped parent materials are S = 1/2 square-lattice antiferromagnets. Sr2CuWO6andSr2CuMoO6 have been found to be quasi-two-dimensional S = 1/2 magnetic systems with a square lattice of Cu-ions. These compounds show low-dimensional magnetic properties, with no clear indication of long-range order in magnetic susceptibility. I will discuss the materials properties and the observation of long range magnetism by neutron diffraction and other techniques. © 2021 American Physical Society