Propagation of ultrasonic waves in neptunium monochalcogenides |
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Authors: | Devraj Singh DK Pandey DK Singh RR Yadav |
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Institution: | aDepartment of Applied Sciences, Amity School of Engineering and Technology, Bijwasan, New Delhi 110 061, India;bDepartment of Physics, P.P.N. (P.G.) College, Kanpur 208 001, India;cDepartment of Physics, Government Inter College, Bangra, Jalaun 285 121, India;dDepartment of Physics, University of Allahabad, Allahabad 211 002, India |
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Abstract: | The ultrasonic attenuation and acoustic coupling constants due to phonon–phonon interaction and thermoelastic relaxation mechanisms have been studied for longitudinal and shear waves in B1 structured neptunium monochalcogenides NpX (X: S, Se, Te) along 〈1 0 0〉 direction in the temperature range 100–300 K. The second and third order elastic constants (SOEC and TOEC) of the chosen monochalcogenides are also computed for the evaluation of ultrasonic parameters. The ultrasonic attenuation due to phonon–phonon interaction process is predominant over thermoelastic relaxation process in these materials. The ultrasonic attenuation in NpTe has been found lesser than other materials NpS, NpSe and GdY (Y: P, As, Sb and Bi). The semiconducting or semimetallic nature of neptunium monochalcogenides can be well understood with the study of thermal relaxation time. Total ultrasonic attenuation in these materials is found to be quadratic function of temperature. The nature of NpTe is very similar to semimetallic GdP. The mechanical and ultrasonic study indicates that NpTe is more reliable, perfect, flawless material. |
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Keywords: | Monochalcogenides Elastic constants Ultrasonic properties |
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