Temperature and pressure manipulation of magnetic ordering and phonon dynamics with phase transition in multiferroic <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>GdFeO</mml:mi><mml:mn>3</mml:mn></mml:msub></mml:math>: Evidence from Raman scattering
Ye Yan, Anyang Cui, Mengyun Bian, Kai Jiang, Liangqing Zhu, Jinzhong Zhang, Liyan Shang, Yawei Li, Zhigao Hu, Junhao Chu
Abstract
We systematically investigate the detailed dynamics of the phonon and local structure of rare-earth orthoferrites ${\mathrm{GdFeO}}_{3}$ single crystal with temperature and pressure induced structural/magnetic phase transition by Raman spectroscopy. Phonon evolution related to the motion of octahedra reveals paramagnetic to antiferromagnetic ordering transition of ${\mathrm{Fe}}^{3+}$ ions at N\'eel temperature ${\phantom{\rule{4pt}{0ex}}T}_{N,Fe}$. By quantifying the polarized Raman spectra, especially the cross-polarized geometry, the lattice dynamics and distortion with local structure rearrangement during ferromagnetic transition has been also discovered. Particularly, we claim that the depolarization ratio could be quantified and used to precisely determine ferromagnetic phase transition of ${\mathrm{GdFeO}}_{3}$ and symmetry evolution simultaneously. Additionally, pressure dependence (up to 25.03 GPa) of collective phonon behavior indicates that antiphase tilt in ${\mathrm{FeO}}_{6}$ octahedra is more susceptible to the stress field than the in-phase one. The ${\mathrm{FeO}}_{6}$ octahedra presents better compressible than ${\mathrm{GdO}}_{12}$ dodecahedra in the ${\mathrm{GdFeO}}_{3}$ lattice with respect to pressure. This work has discovered the physical mechanism underlying variation of local structural symmetry, octahedra tilt, and phonon dynamics in ${\mathrm{GdFeO}}_{3}$, which can be regarded as the basic view for a series of ${\mathrm{GdFeO}}_{3}$-type perovskites and more R${\mathrm{FeO}}_{3}$ system.