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Relaxor ferroelectrics: Cluster glass ground state via random fields and random bonds
Author(s) -
Kleemann Wolfgang
Publication year - 2014
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201350310
Subject(s) - materials science , mesoscopic physics , condensed matter physics , cluster (spacecraft) , ferroelectricity , ground state , polar , dielectric , phase transition , physics , quantum mechanics , optoelectronics , computer science , programming language
Quenched random fields (RFs) are well‐known to be a basic driving force of the relaxor behavior in disordered ferroelectrics containing either random charges as in PbMg 1/3 Nb 2/3 O 3 or random cation vacancies as in Sr x Ba 1− x Nb 2 O 6 . They give rise to the formation of polar nanoregions in the paraelectric regime, which freeze into a nanodomain state at low temperatures thus precluding the ferroelectric phase transition. On the other hand, isovalent relaxors like bond‐disordered BaTi 1− x Zr x O 3 prevalently experience random bonds (RBs), which are responsible for glassy features such as polydispersivity and non‐ergodic aging and rejuvenation processes. Inspection shows, however, that all of the above characteristics apply generally to relaxor systems albeit with different weight. Subsequent formation of ferroic nanoregions via RFs followed by mesoscopic cluster glassy freezing via RBs upon cooling are universal signatures.