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Temperature-Dependent Raman Spectroscopy of Lead-Free (Na$_{0.5}$K$_{0.5}$)NbO$_3$ Ceramics
New Phys.: Sae Mulli 2017; 67: 1279~1283
Published online November 30, 2017;
© 2017 New Physics: Sae Mulli.

Ho Sueb LEE1, Hyo-Eun KIM1, Jin Soo KIM*1, Kwang-Sei LEE2

1 Department of Physics and Center for Research Facilities, Changwon National University, Changwon 51140, Korea
2 Department of Nano Science & Engineering, Center for Nano Manufacturing, Inje  University, Gimhae 50834, Korea
Correspondence to:
Received August 16, 2017; Revised September 12, 2017; Accepted September 27, 2017.
cc This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
We have synthesized lead-free (Na$_{0.5}$K$_{0.5}$)NbO$_3$ (NKN) ceramics and used Raman spectroscopy to investigate the temperature dependences of the internal vibrational mode. With increasing temperature, the Raman peaks broadened and the peak frequency shifted to lower frequency. Especially, changes in the Raman peak's frequency were observed at the phase transitional temperatures of $T_{O-T}$ (orthorhombic-tetragonal) and $T_c$ (tetragonal-cubic). We discuss the temperature dependences of the Raman spectra related to the internal vibrations of NbO$_6$ octahedra and compared the results to dielectric behavior.
PACS numbers: 77.22.-d, 77.84.Dy, 77.84.-s
Keywords: (Na$_{0.5}$K$_{0.5}$)NbO$_3$, NKN, Lead-free, Ferroelectric, Raman spectra 

March 2018, 68 (3)
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