Charge Order and Negative Thermal Expansion in V2OPO4

Elise Pachoud, James Cumby, Calum T. Lithgow, J. Paul Attfield*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

The semivalent oxyphosphate V2OPO4 is found to have long-range V2+/V(3+)charge ordering up to 605 K where a monoclinic to tetragonal structural transition and a switch from positive to negative' thermal expansion are observed. V-V bonding within orbital polymer chains is proposed as the key factor in the novel switch of thermal expansion behavior, as loss of V-V bonding enables transverse oxygen motions to dominate the thermal' expansion at high temperatures. Ferrimagnetic order of V2+ spin up and V3+ spin down states is observed below a magnetic ordering transition at 164 K, and susceptibility measurements evidence local spin pairing correlations to higher temperatures.

Original languageEnglish
Pages (from-to)636-641
Number of pages6
JournalJournal of the American Chemical Society
Volume140
Issue number2
Early online date19 Dec 2017
DOIs
Publication statusPublished - 17 Jan 2018

Keywords

  • ELECTRONIC-STRUCTURE CALCULATIONS
  • POPULATION ANALYSIS
  • TRANSITION
  • OXIDES

Cite this