Crystal structure and magnetic properties of the Ba{sub 3}TeCo{sub 3}P{sub 2}O{sub 14}, Pb{sub 3}TeCo{sub 3}P{sub 2}O{sub 14}, and Pb{sub 3}TeCo{sub 3}V{sub 2}O{sub 14} langasites
- Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6393 (United States)
- Department of Physics, Technical University of Denmark, 2800 Kgs. Lyngby (Denmark)
- Department of Chemistry, Princeton University, Princeton, NJ 08544 (United States)
We report the structural and magnetic characterizations of Ba{sub 3}TeCo{sub 3}P{sub 2}O{sub 14}, Pb{sub 3}TeCo{sub 3}P{sub 2}O{sub 14}, and Pb{sub 3}TeCo{sub 3}V{sub 2}O{sub 14}, compounds that are based on the mineral dugganite, which is isostructural to langasites. The magnetic part of the structure consists of layers of Co{sup 2+} triangles. Nuclear and magnetic structures were determined through a co-refinement of synchrotron and neutron powder diffraction data. In contrast to the undistorted P321 langasite structure of Ba{sub 3}TeCo{sub 3}P{sub 2}O{sub 14}, a complex structural distortion yielding a large supercell is found for both Pb{sub 3}TeCo{sub 3}P{sub 2}O{sub 14} and Pb{sub 3}TeCo{sub 3}V{sub 2}O{sub 14}. Comparison of the three compounds studied along with the zinc analog Pb{sub 3}TeZn{sub 3}P{sub 2}O{sub 14}, also characterized here, suggests that the distortion is driven by Pb{sup 2+} lone pairs; as such, the Pb compounds crystallize in a pyroelectric space group, P2. Magnetic susceptibility, magnetization, and heat capacity measurements were performed to characterize the magnetic behavior. All three compounds become antiferromagnetic with Néel temperatures T{sub N}≈21 K (Ba{sub 3}TeCo{sub 3}P{sub 2}O{sub 14}), ≈13 K (Pb{sub 3}TeCo{sub 3}P{sub 2}O{sub 14}), and ≈8 K (Pb{sub 3}TeCo{sub 3}V{sub 2}O{sub 14}), and they exhibit magnetic transitions at high applied magnetic fields, suggesting intrinsically complex magnetic behavior for tetrahedrally coordinated d{sup 7} Co{sup 2+} in this structure type. - Graphical abstract: Ba{sub 3}TeCo{sub 3}P{sub 2}O{sub 14}, Pb{sub 3}TeCo{sub 3}P{sub 2}O{sub 14} and Pb{sub 3}TeCo{sub 3}V{sub 2}O{sub 14} exhibit a triangles-of-triangles arrangement of the magnetic cations. Despite the Pb-induced crystallographic distortion, all of these materials exhibit competing antiferromagnetic and ferromagnetic interactions that lead to complex high field magnetism. - Highlights: • Nuclear and magnetic structures of Ba{sub 3}TeCo{sub 3}P{sub 2}O{sub 14}, Pb{sub 3}TeCo{sub 3}P{sub 2}O{sub 14} and Pb{sub 3}TeCo{sub 3}V{sub 2}O{sub 14}. • Structural characterization shows complex Pb-induced distortion. • Distortion puts Pb-compounds into space group that allows potential multiferroicity. • Magnetic characterization shows competing magnetic interactions. • Triangles of triangles motif results in complex high-field magnetic behavior.
- OSTI ID:
- 22309052
- Journal Information:
- Journal of Solid State Chemistry, Vol. 203; Other Information: Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
- Country of Publication:
- United States
- Language:
- English
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