Bipolar electrocaloric effect in Pb1-xGdx(Mg1+x/3Nb2-x/3)O3 ceramic: Relaxor with super-dipolar glass state

SCRIPTA MATERIALIA

卷:162

Article

Pandey, Adityanarayan H.^1,2  Awasthi, A. M.³  Gupta, Surya Mohan^1,2 

[1] Homi Bhabha Natl Inst, Mumbai 400094, India

[2] Raja Ramanna Ctr Adv Technol, Laser Mat Sect, Indore 452013, Madhya Pradesh, India

[3] UGC DAE Consortium Sci Res, Univ Campus,Khandwa Rd, Indore 452001, Madhya Pradesh, India

关键词: Relaxor ferroelectric;    Lead magnesium niobate;    Critical slowing down;    Electrocaloric;    Field induced polarization switching;   

DOI  :  10.1016/j.scriptamat.2018.10.027

来源: Elsevier

【 摘 要 】

The electrocaloric (EC) effect is calculated for Pb1-xGdx(Mg1+x/3Nb2-x/3)O-3; 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 Smax is observed to decrease from similar to 0.4 K-mm/KV at 164 K to similar to 0.1 K-mm/kV with x. (C) 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

【 授权许可】

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