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Single-crystal growth, crystallography, magnetic susceptibility, heat capacity, and thermal expansion of the antiferromagnetic S=1 chain compound CaV2O4
Physical Review B
  • A. Niazi, Iowa State University
  • Sergey L. Bud'ko, Iowa State University
  • Deborah L. Schlagel, Iowa State University
  • J.-Q. Yan, Iowa State University
  • Thomas A. Lograsso, Iowa State University
  • Andreas Kreyssig, Iowa State University
  • S. Das, Iowa State University
  • Shibabrata Nandi, Iowa State University
  • Alan I. Goldman, Iowa State University
  • A. Honecker, Universität Göttingen
  • R. William McCallum, Iowa State University
  • M. Reehuis, Helmholtz-Zentrum Berlin für Materialien und Energie (HZB)
  • O. Pieper, Technische Universität Berlin
  • B. Lake, Technische Universität Berlin
  • David C. Johnston, Iowa State University
Document Type
Article
Publication Date
3-27-2009
DOI
10.1103/PhysRevB.79.104432
Abstract

The compound CaV2O4 contains V+3 cations with spin S=1 and has an orthorhombic structure at room temperature containing zigzag chains of V atoms running along the c axis. We have grown single crystals of CaV2O4 and report crystallography, static magnetization, magnetic susceptibility χ, ac magnetic susceptibility, heat capacity Cp, and thermal expansion measurements in the temperature T range of 1.8–350 K on the single crystals and on polycrystalline samples. An orthorhombic-to-monoclinic structural distortion and a long-range antiferromagnetic (AF) transition were found at sample-dependent temperatures TS≈108–145 K andTN≈51–76 K, respectively. In two annealed single crystals, another transition was found at ≈200 K. In one of the crystals, this transition is mostly due to V2O3 impurity phase that grows coherently in the crystals during annealing. However, in the other crystal the origin of this transition at 200 K is unknown. The χ(T) shows a broad maximum at ≈300 K associated with short-range AF ordering and the anisotropy of χ above TN is small. The anisotropic χ(T→0) data below TN show that the (average) easy axis of the AF magnetic structure is the b axis. The Cp(T) data indicate strong short-range AF ordering above TN, consistent with the χ(T) data. We fitted our χ data by a J1-J2 S=1 Heisenberg chain model, where J1(J2) is the (next)-nearest-neighbor exchange interaction. We find J1≈230 K and surprisingly, J2/J1≈0 (or J1/J2≈0). The interaction J⊥ between these S=1 chains leading to long-range AF ordering at TN is estimated to be J⊥/J1≳0.04.

Comments

This article is from Physical Review B 79 (2009): 104432, doi:10.1103/PhysRevB.79.104432.

Copyright Owner
American Physical Society
Language
en
Date Available
2013-09-21
File Format
application/pdf
Citation Information
A. Niazi, Sergey L. Bud'ko, Deborah L. Schlagel, J.-Q. Yan, et al.. "Single-crystal growth, crystallography, magnetic susceptibility, heat capacity, and thermal expansion of the antiferromagnetic S=1 chain compound CaV2O4" Physical Review B Vol. 79 Iss. 10 (2009) p. 104432
Available at: http://works.bepress.com/thomas_lograsso/67/