K.W. Blazey, K.A. Müller, et al.
Solid State Communications
Inelastic-neutron-scattering measurements have been performed on the high-temperature cubic perovskite phase of LaAlO3. Dispersion curves for phonons with q along [111] establish that near the zone corner (R point), the frequency of the lowest branch is both anomalously low and temperature-dependent. The nature of the associated scattering changes continuously from inelastic to quasi-elastic as the temperature is lowered, indicating that the soft-phonon modes become overdamped. The intensity of this quasi-elastic scattering exhibits a Curie-law divergence as the temperature is lowered further toward the transformation temperature of (535±5)°C. The displacements associated with the rhombohedral low-temperature structure result from the condensation of a particular linear combination of these soft triply degenerate Γ25 modes, as proposed by Cochran and Zia. © 1969 The American Physical Society.
K.W. Blazey, K.A. Müller, et al.
Solid State Communications
K.A. Müller, W. Berlinger, et al.
Physical Review Letters
K.A. Müller, W. Berlinger
Physical Review Letters
E. Siegel, K.A. Müller
Physical Review B