Bipolar electrocaloric effect in Pb1−xGdx(Mg1+x/3Nb2–x/3)O3 ceramic: Relaxor with super-dipolar glass state. (15th March 2019)

• Record Type: Journal Article
• Authors: Pandey, Adityanarayan H.; Awasthi, A.M.; Gupta, Surya Mohan
• Is Part Of: Scripta materialia. Number 162(2019)
• Page Start: 1
• Page End: 4
• Publication Date: 2019-03-15
• Subjects: Relaxor ferroelectric -- Lead magnesium niobate -- Critical slowing down -- Electrocaloric -- Field induced polarization switching; Materials -- Periodicals; Metallurgy -- Periodicals; Metalen; Legeringen; Materiaalkunde; Metals, metalworking and machinery industries; Metals; Electronic journals; 620.11
• DOI: 10.1016/j.scriptamat.2018.10.027
• Languages: English
• ISSNs: 1359-6462

Abstract

Abstract: The electrocaloric (EC) effect is calculated for Pb1− x Gd x (Mg1+ x /3 Nb2– x /3 )O3 ; x = 0 to 0.1 relaxors from temperature dependent heat capacity and polarization measurements, using a thermodynamic Maxwell equation. Polarization change with temperature reveals an anomalous behaviour around the glass transition temperature for x ≥ 0.05, which is in the vicinity of a crossover from positive to negative EC effect, which is explained evoking the critical slowing-down of the polar nano-domains dynamics to super-dipolar glass state upon cooling. The maximum negative EC coefficient ξmax is observed to decrease from ~0.4 K-mm/kV at 164 K to ~0.1 K-mm/kV with x . Graphical abstract: Unlabelled Image