Dediu V, Ferdeghini C, Matacotta FC, Nozar P, Ruani G
Istituto di Spettroscopia Molecolare, CNR, via Gobetti 101, 40129 Bologna, Italy.
Phys Rev Lett. 2000 May 8;84(19):4489-92. doi: 10.1103/PhysRevLett.84.4489.
The Raman spectra of the charge-ordered manganite Pr0.65Ca0.35MnO3 were studied as functions of temperature and excitation energy and compared to magnetic moment and electrical conductivity behaviors. Both the charge ordering ( T(co) approximately 225 K) and the antiferromagnetic transitions ( T(N) approximately 175 K) affect the spectral shape and intensity, indicating strong charge-lattice and spin-lattice couplings. Below T(co) a transition from dynamic Jahn-Teller distortions to a collective static distortion takes place. A change of the spectra is observed on increasing the excitation energy above 2.5 eV and it is attributed to a resonant polaron excitation.
研究了电荷有序锰氧化物Pr0.65Ca0.35MnO3的拉曼光谱随温度和激发能量的变化，并与磁矩和电导率行为进行了比较。电荷有序（T(co)约225 K）和反铁磁转变（T(N)约175 K）均影响光谱形状和强度，表明存在强电荷-晶格和自旋-晶格耦合。在T(co)以下，发生了从动态 Jahn-Teller 畸变到集体静态畸变的转变。当激发能量增加到2.5 eV以上时，观察到光谱发生变化，这归因于共振极化子激发。
