Mansouri S, Charpentier S, Jandl S, Fournier P, Mukhin A A, Ivanov V Yu, Balbashov A
Département de Physique, Université de Sherbrooke, 2500 Boulevard Université, Sherbrooke, Québec J1K 2R1, Canada.
J Phys Condens Matter. 2009 Sep 23;21(38):386004. doi: 10.1088/0953-8984/21/38/386004. Epub 2009 Aug 27.
We present a micro-Raman study of a high quality Pr(0.5)Ca(0.5)MnO(3) single crystal and thin films on SrTiO(3) and LaAlO(3) substrates. Ten A(g) and seven B(2g) Raman-active modes (simplified symmetry: Pmma space group) have been observed and correlated to charge ordering around T(co) = 240 K and antiferromagnetic spin-orbital ordering at T(N)∼ 170 K. Our data reveal that coherent Jahn-Teller MnO(6) distortions prevail at T<T(N). Moreover, the temperature dependence of the frequency and linewidth of the A(g) mode corresponding to in-plane oxygen atom rotation (∼268 cm(-1)) is analyzed within a polaron-like scheme that reflects a strong charge ordering to lattice coupling. The close similarities between the single crystal and the thin films' phonon evolution confirm that the thin films growth conditions have been optimized.
