Anomalous structural behavior and antiferroelectricity in BiGdO3: detailed temperature and high-pressure study. (29th September 2021)

• Record Type: Journal Article
• Authors: Jana, Rajesh; Dutta, Apurba; Saha, Pinku; Mandal, Kapil; Ghosh, Bishnupada; Chandra, Amreesh; Das, I; Mukherjee, Goutam Dev
• Is Part Of: Journal of physics. Volume 33:Number 49(2021)
• Publication Date: 2021-09-29
• Subjects: antiferroelectrics -- dielectric properties -- pressure effect -- structural transition -- x-ray diffraction -- Raman spectroscopy; Condensed matter -- Periodicals; Matière condensée -- Périodiques; Vaste stoffen; Vloeistoffen; Natuurkunde; Electronic journals; Computer network resources; 530.4105
• DOI: 10.1088/1361-648X/ac2646
• Languages: English
• ISSNs: 0953-8984

Abstract

Abstract: A comprehensive temperature and high-pressure investigation on BiGdO3 is carried out by means of dielectric constant, piezoelectric current, polarization-electric field loop, Raman scattering and x-ray diffraction measurements. Temperature dependent dielectric constant and dielectric loss show two anomalies at about 290 K ( T r ) and 720 K ( T C ). The latter anomaly is most likely due to antiferroelectric to paraelectric transition as hinted by piezoelectric current and polarization-electric field loop measurements at room temperature, while the former anomaly suggests reorientation of polarization. A small deviation from linear behaviour of both the Raman modes due to structural modification in the vicinity of T C ; and sharp decrease in integrated intensities of these two modes above T C provide further proof for the above antiferroelectric to paraelectric transition. Cubic to monoclinic structural transition is observed at about 10 GPa in high-pressure x-ray diffraction studies accompanied by anisotropic lattice parameter changes and large unit cell volume collapse during the transition. This structural transition is corroborated by anomalous softening and large increase in full width half maximum of M2 (640 cm −1 ) Raman mode above 10 GPa. We speculate that enhancement of large structural distortion and large reduction in c / a ratio above 10 GPa might be associated with antiferroelectric to ferroelectric transition in the system.