Pressure evolution of resistance in framework structured materials α -ZrMo2O8 and α -HfMo2O8

Karandikar, A. S. ; Mukherjee, G. D. ; Vijayakumar, V. ; Godwal, B. K. ; Achary, S. N. ; Tyagi, A. K. (2006) Pressure evolution of resistance in framework structured materials α -ZrMo2O8 and α -HfMo2O8 Journal of Applied Physics, 100 (1). 013517_1-013517_7. ISSN 0021-8979

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Official URL: http://link.aip.org/link/?JAPIAU/100/013517/1

Related URL: http://dx.doi.org/10.1063/1.2211312

Abstract

The ac resistance measurements on the trigonal (α -) phase of ZrMo2O8 and HfMo2O8 carried out up to 5 GPa using the toroid anvil apparatus are reported. The ac resistance data in both the materials are found to be strongly frequency dependent and show a transition between two power law regimes with a crossover frequency (ω c) near 1 kHz. For both the compounds slope changes and anomalies are observed in the ac resistance data at the structural transition pressures. The activation volumes at room temperature are obtained by analyzing the ac conductance data in terms of the pressure dependent activation volume model. The main conduction mechanism at 12 Hz is believed to be the diffusion of oxygens ions, whereas hopping of point defects is responsible for ac conductuance above 33 kHz. At 1 KHz, a crossover from hopping to diffusion of point defects is observed at the α -δ (monoclinic) phase transition pressure.

Item Type:Article
Source:Copyright of this article belongs to American Institute of Physics.
ID Code:11995
Deposited On:10 Nov 2010 05:11
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