Low Temperature Physics: 44, 434 (2018); https://doi.org/10.1063/1.5034155
Fizika Nizkikh Temperatur: Volume 44, Number 5 (May 2018), p. 568-572    ( to contents , go back )

X-ray absorption near edge spectroscopy of thermochromic phase transition in CuMoO4

I. Jonane1, A. Cintins1, A. Kalinko2, R. Chernikov3, and A. Kuzmin1

1Institute of Solid State Physics, University of Latvia, 8 Kengaraga Str., Riga LV-1063, Latvia
E-mail: inga.jonane@cfi.lu.lv

2Universität Paderborn, Naturwissenschaftliche Fakultät, Department Chemie, 100 Warburger Str., Paderborn 33098, Germany

3DESY Photon Science, 85 Notkestraße, Hamburg D-22607, Germany

Received October 26, 2017


Thermochromic phase transition was studied in CuMoO4 using the Cu and Mo K-edge x-ray absorption spectroscopy in the temperature range of 10–300 K. The hysteretic behavior has been evidenced from the temperature dependence of the pre-edge shoulder intensity at the Mo K-edge, indicating that the transition from brownish-red γ-CuMoO4 to green α-CuMoO4 occurs in the temperature range of 230–280 K upon heating, whereas the α-to-γ transition occurs between 200 and 120 K upon cooling. Such behavior of the pre-edge shoulder at the Mo K-edge correlates with the change of molybdenum coordination between distorted tetrahedral in α-CuMoO4 and distorted octahedral in γ-CuMoO4. This result has been supported by ab initio full-multiple-scattering x-ray absorption near edge structure (XANES) calculations.

PACS: 61.05.cj X-ray absorption spectroscopy: EXAFS, NEXAFS, XANES, etc.;
PACS: 64.70.kp Ionic crystals.

Key words: x-ray absorption spectroscopy, CuMoO4, thermochromism, phase transition.

Published online: March 27, 2018

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