Effects of cation disorder on terahertz emission from half-doped manganite thin filmsK. R. Mavani, D. S. Rana, K. Takahashi, I. Kawayama, H. Murakami and M. Tonouchi
Institute of Laser Engineering, Osaka University - 2-6 Yamadaoka, Suita, Osaka 565-0871, Japan
received 13 August 2007; accepted in final form 31 October 2007; published January 2008
published online 6 December 2007
We have observed terahertz (THz) emission from antiferromagnetic charge-ordered "undoped" Nd0.5Ca0.5MnO3 and "Ba-doped" Nd0.5Ca0.48Ba0.02MnO3 manganites by illuminating femtosecond laser pulses on the optical switch fabricated on highly oriented thin films. The THz emission and the magnetic characteristics of these manganite thin films are studied and compared. The THz emission shows strongly temperature-dependent characteristics. A pronounced broad peak is observed at the charge-ordering transition in the temperature-dependent THz emission of the films. On a comparison of the results of both the films, this peak is found largely suppressed for Ba-doped manganite. These results, corroborated by the magnetization of films, reveal a role of the A-site cation disorder in affecting the THz emission from ABO3-type charge-ordered manganites.
75.47.Lx - Manganites.
78.66.-w - Optical properties of specific thin films.
78.20.Jq - Electrooptical effects.
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