Temperature-dependent Brillouin scattering studies of surface acoustic modes in Nd0.5Sr0.5MnO3 |
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Authors: | Md.Motin Seikh Chandrabhas NarayanaSachin Parashar A.K. Sood |
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Affiliation: | a Chemistry and physics of materials unit, Jawaharlal Nehru Center for Advanced Scientific Research, Jakkur P.O., Bangalore 560 064, India b Solid Sate and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560 012, India c Department of Physics, Indian Institute of Science, Bangalore 560 012, India |
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Abstract: | Brillouin scattering experiments are carried out to study the surface acoustic waves in Nd0.5Sr0.5MnO3 as a function of temperature in the range of 40-300 K covering the metal-insulator and charge-ordering phase transitions. The surface modes include surface Rayleigh wave, pseudo-surface acoustic wave (PSAW) and high velocity PSAW. The observed softening of the sound velocities for the surface modes below paramagnetic to ferromagnetic transition, Tc is related to the softening of the C44 elastic constant. The subsequent hardening of the sound velocity below the charge ordering transition temperature Tco is attributed to the coupling of the acoustic phonon to the charge ordered state via long range ordering of the strong Jahn-Teller (JT) distortion. |
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Keywords: | 78.35.+c |
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