Sains Malaysiana 51(9)(2022): 3095-3101

http://doi.org/10.17576/jsm-2022-5109-28

Atenuasi Ultrasonik dan Modulus Ricih pada Suhu Genting Superkonduktor Terdop Sederhana (Tl_0.8Bi_0.2)Sr₂(Ca_0.9Cr_0.1)Cu₂O₇

(Ultrasonic Attenuation and Shear Modulus at the Critical Temperature of Moderately Doped

(Tl_0.8Bi_0.2)Sr₂(Ca_0.9Cr_0.1)Cu₂O₇ Superconductor)

R. ABD-SHUKOR^1,*, L.K. TAN¹, NOR AZAH NIK-JAAFAR² & M.N. MOHD NASIR¹

¹Department of Applied Physics, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor Darul Ehsan, Malaysia

²Pusat GENIUS@Pintar Negara, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor Darul Ehsan, Malaysia

Diserahkan: 5 Mac 2021/Diterima: 14 Jun 2022

Abstrak

Modulus ricih dan atenuasi ultrasonik superkonduktor suhu tinggi terdop sederhana (Tl_0.8Bi_0.2)Sr₂(Ca_0.9Cr_0.1)Cu₂O₇ (Tl-1212) dengan suhu genting (T_c ) 98 K telah dikaji.  Modulus ricih, G meningkat apabila suhu diturunkan daripada 240 K ke 80 K yang menunjukkan pengerasan kekisi.  Walau bagaimanapun, pada suhu antara 160 K hingga 190 K modulus ricih menunjukkan anomali menandakan kecenderungan untuk kekisi melembut.  Berhampiran suhu genting modulus ricih menunjukkan pelembutan kekisi iaitu ketakselanjaran pada cerun (dG/dT) dan ini sejajar dengan ciri peralihan fasa termodinamik tertib ke dua.  Peratus perubahan modulus ricih antara 240 K dan 80 K ialah 5.5%.  Atenuasi ultrasonik menunjukkan penurunan mendadak daripada 240 K ke 210 K diikuti dengan profil yang hampir mendatar sehingga 140 K.  Puncak atenuasi dicerap berhampiran suhu genting dan ini menunjukkan penyerapan tenaga akustik meningkat apabila bahan memasuki fasa mensuperkonduksi.  Anomali modulus ricih dan atenuasi ultrasonik ini dijelaskan melalui peralihan fasa tertib kedua dan tertiban oksigen jarak dekat dalam satah Cu-O unit sel bahan superkonduktor ini.

Kata kunci: Getaran kekisi; mikrostruktur; peralihan fasa; sifat akustik

Abstract

The shear modulus and ultrasonic attenuation of a moderately doped (Tl_0.8Bi_0.2)Sr₂(Ca_0.9Cr_0.1)Cu₂O₇ (Tl-1212) high temperature superconductor with critical temperature (T_c) of 98 K have been studied.  The shear modulus, G increased when the temperature was lowered from 240 K to 80 K indicating lattice hardenings. However, at temperatures between 160 K and 190 K, the shear modulus showed an anomaly indicating a lattice softening tendency.  Near the critical temperature the shear modulus showed lattice softenings i.e., a discontinuity in the slope (dG/dT) and this is consistent with the characteristic of a second-order thermodynamic phase transition.  The percent change in shear modulus between 240 K and 80 K was 5.5 %.  Ultrasonic attenuation showed a sharp decrease from 240 K to 210 K followed by a near horizontal profile to 140 K.  An attenuation peak was observed near the critical temperature and this indicated an increase in acoustic energy absorption as the material entered the superconducting phase.  The shear modulus and ultrasonic attenuation anomalies were explained using the second-order phase transition and short-range oxygen orderings in the Cu-O plane of the cell unit of this superconducting material.

Keywords: Acoustic properties; lattice vibration; microstructure; phase transition

Rujukan

Abd-Shukor, R. 2018.  Ultrasonic and elastic properties of Tl- and Hg-based cuprate superconductors: a review. Phase Transitions 91: 48-57.

Abd-Shukor, R. 1997. Ultrasonic shear velocity anomalies in bulk thallium-1212 high T_c superconductors. Modern Physics Letters B 11(8): 359-365.

Alers, G.A. 1966. The measurement of very small sound velocity changes and their use in the study of solids. In Physical Acoustics 4A, edited by Mason, W.P. New York: Academic Press. hlm. 277.

Bhattacharya, S., Higgins, M.J., Johnston, D.C., Jacobson, A.J., Stokes, J.P., Goshorn, D.P. & Lewandowski, J.T. 1988. Elastic anomalies and phase transitions in high-T_c superconductors. Physical Review Letters 60: 1181-1184.

Klehe, A-K., Looney, C., Schilling, J.S., Takahashi, H., Mori, N., Shimakawa, Y., Kubo, Y., Manako, T., Doyle, S. & Hermann, A.M. 1996.  Pressure-induced oxygen ordering phenomena in high-T_c superconductors. Physica C 257: 105-116.

Ledesert, M., Maignan, A., Chardon, J., Martin, C., Rh. Labbe, Hervieu, M. & Raveau, B. 1994. (Tl,Bi)Sr₂CaCu₂O₇ “1212” superconducting single crystal - A structural and magnetic study. Physica C 232: 387-395.

Mamsurova, L.G., Pigalskiy, K.S., Sakun, V.P., Shushin, A.I. & Scherbakova, L.G. 1990. First- and second-order phase transitions and oxygen rearrangement over the Cu1-O4 chains in orthorhombic YBa₂Cu₃O_6+x at low temperatures. Physica C 167: 11-19.

Neeleshwar, S., Muralidhar, M., Murakami, M. & Venugopal Reddy, P. 2006. Elastic behavior of oxygen controlled melt growth processed NEG-123 HTSC materials. International Journal of Modern Physics B 20: 667-675.

Shtyk, A.V. & Feigel’man, M.V. 2016. Ultrasonic attenuation in a pseudogapped superconductor. ArXive. cond-mat.supr-con. 1609.01683v1.

Sun, K.J., Winfree, W.P., Xu, M-F., Levy, M., Sarma, B.K., Singh, A.K., Osofsky, M.S. & Le Tourneau, V.M. 1990. Enhanced ultrasonic attenuation of Tl-Ca-Ba-Cu-O at the superconducting transition. Physical Review B 42(4): 2569-2572.

Testardi, R.L. 1975. Elastic modulus, thermal expansion and specific heat at the phase transition. Physical Review B 12: 3849-3854.

Toulose, J., Wang, X.M. & Hong, D.L.J. 1988. Ultrasonic evidence for a structural phase transition at 220 K in YBa₂Cu₃O_7−δ. Physical Review B 38: 7077-7079.

Vui, C.T. & Abd-Shukor, R. 2016. Ultrasonic attenuation anomalies of n-type superconductor Pr_2-xCe_xCuO₄. Modern Physics Letters B 30: 1650314.

Yahya, A.K. & Abd-Shukor, R. 1998. Ultrasonic velocity studies on Tl₂Ba₂Ca₂Cu₃O₁₀ superconductor. Modern Physics Letters B 12(24): 1029-1037.

Yusrianto, Y., Jannah, A.N. & Abd-Shukor, R. 2021.  Pembentukan fasa dan suhu genting superkonduktor (Tl_0.5Pb_0.5)Sr₂Ca(Cu_2-xCr_x)O_{7 (}x = 0 - 0.100). Sains Malaysiana 50(6): 1775-1786.

Zhang, L., Ying, X.N. & Yuan, Y.H. 2011. Internal friction study on bilayer cuprates Pr(Ba_1−xSr_x)₂Cu₃O_7−δ. Physica C 471: 62-65.

Zhou, H.L., Huang, Y.N., Zhu, J.S. & Wang, Y.N. 1995.  Internal friction related to carriers in Hg-system superconductors. Physica Status Solidi (a) 150(2): 743-748.

^*Pengarang untuk surat-menyurat; email: ras@ukm.edu.my