Engineering crystal structure and spin-phonon coupling in Ba1-xSrxMnO3

The interplay between different degrees of freedom such as charge, spin, orbital, and lattice has received a great deal of interest due to its potential to engineer materials properties and their functionalities for device applications. In this work, we have explored the crystallographic phase diagram of Ba1-xSrxMnO3 and studied the correlation between two degrees of freedom, namely phonons and spins using magnetization and inelastic light scattering measurements. The system undergoes a series of crystallographic phase transitions 2H -> 9R -> 4H as a function of doping (Sr) as observed by X-ray diffraction measurements. Investigation of their temperature dependent magnetization reveals a para-to antiferro-magnetic transition for all the compositions. An E-g phonon in the 9R phase and an E-1g phonon in the 4H phase involving Mn/O-vibrations, show anomalous temperature-dependence in the antiferromagnetic phase arising due to spin-phonon coupling.

Automated summary

This study explores the crystallographic phase diagram of Ba1-xSrxMnO3 and the correlation between phonons and spins through magnetization and inelastic light scattering measurements. The system undergoes a series of crystallographic phase transitions as a function of Sr doping, with all compositions showing a paramagnetic-to-antiferromagnetic transition. Anomalous temperature dependence of phonons in specific phases is observed due to spin-phonon coupling.