Raman spectroscopy of SrRuO3 near the paramagnetic-to-ferromagnetic phase transition

The polarized Raman spectra of (010)- and (001)-oriented epitaxial thin fil ms of SrRuO3 (space group Pnma, Z=4) are measured between 5 and 300 K. The Raman lines at 123, 225, 252, 291, 361, 390-393, and 412 cm(-1) are assigne d to definite modes of A(g) or B-2g symmetry based of their polarization se lection rules, the comparison with the results of lattice dynamical calcula tions (LDC), and accounting for the correlation between the Gamma-point pho nons in the Pnma structure and the Gamma-, R-, X-, and M-point phonon modes in the parent Pm (3) over bar m structure. The pronounced anomalies of the Raman phonon parameters near the ferromagnetic transition (T-c=148 K) are discussed in terms of enhanced spin-phonon coupling and reorganization of t he electronic states in the vicinity of T-c. [S0163-1829(99)12301-4].