| Original Articles |
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Thermal Diffusivity of Ordered Double Perovskite A2FeMoO6
( A = Ca, Sr and Ba) |
| LIU Xiao-Jun1;HUANG Qiao-Jian1;NIU Dong-Lin1;XU Sheng2;ZHANG Shu-Yi1 |
| 1State Key Laboratory of Modern Acoustics and Institute of Acoustics, Nanjing University, Nanjing 210093
2Department of Crystalline Materials Science, Nagoya University, Nagoya 464-8601, Japan |
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| Cite this article: |
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LIU Xiao-Jun, HUANG Qiao-Jian, NIU Dong-Lin et al 2004 Chin. Phys. Lett. 21 2281-2284 |
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Abstract Thermal diffusivity has been investigated in ordered double perovskite Sr2FeMoO6 by means of transient surface grating technique in the temperature range of 300--450K. The thermal diffusivity shows an appreciable decrease from 39 mm2/s at 300 K to 37 mm2/s at 360 K in the ferromagnetic phase, and then steeply drops to 10 mm2/s with further increasing temperature above the critical temperature Tc～380 K. Such an abrupt decrease of the thermal diffusivity has been ascribed to the structural phase transition at Tc. We further investigate the lattice effect on the thermal diffusivity in A2FeMoO6 (A= Ca, Sr and Ba) by substitution of Ca2+ or Ba2+ ions for Sr2+ ions at 300 K. We find that the thermal diffusivity increases from 35 mm2/s for A= Ca to 41 mm2/s for A= Ba. Considering the change of the Fe--O--Mo bond angle from 152.4°C for A= Ca to 180°C for A= Ba, the increased thermal diffusivity for Ba compound has been ascribed to the enhanced hybridization between transition-metal d and oxygen p states due to the larger Fe--O--Mo bond angle and hence the wider one-electron bandwidth
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| Keywords:
74.62.Dh
71.30.+h
72.80.Ga
66.30.Xj
67.55.Hc
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Published: 01 November 2004
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| PACS: |
74.62.Dh
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(Effects of crystal defects, doping and substitution)
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71.30.+h
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(Metal-insulator transitions and other electronic transitions)
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72.80.Ga
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(Transition-metal compounds)
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66.30.Xj
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(Thermal diffusivity)
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67.55.Hc
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