Polarized Raman scattering spectra of PrBa2Cu4O8 were studied in the temperature range 10 to 300 K. An anomalous temperature dependence of the two-magnon peak was found, which softens upon cooling from about 2590 cm-1 at 300 K to 2480 cm-1 at 10 K. The observed behavior is opposite to what is known for RBa2Cu3O6, R2CuO4 (R = rare earth) and KMnF3-type antiferromagnets, where the two-magnon peak shifts to higher frequencies upon decreasing the in-plane Cu-O bond length due to either lowering temperature or applying pressure. The experimental data are discussed in view of the semiconductor-metal transition which, according to recent optical and transport studies, occurs in PrBa2Cu4O8 at T* ≈ 150 K.
|Number of pages||6|
|Journal||Physica Status Solidi (B) Basic Research|
|Publication status||Published - 1999 Sep|
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics