Relaxor ferroelectrics and related superglasses

Abstract

Mesoscopic ferroic glasses such as martensitic strain glass Ti_50−x Ni_50+x, magnetic cluster glass La_0.7Ca_0.3Mn_0.7Cd_0.3O₃, and superdipolar relaxor PbMg_1/3Nb_2/3O₃ (PMN) undergo glass transitions preceded by mesoscopic precursor patterns – elastic or magnetic tweed or polar nanoregions (PNR), respectively. In PMN the PNR glass transition at T_g ≈ 240 K reveals glassy dynamic criticality and non-ergodicity of the field-induced low-T phase similar to that of a superspin glass of fixed magnetic nanoparticles in a diamagnetic environment. A final ferroelectric domain state is reached at T_p ≈ 213 K via PNR percolation, which is absent in weak relaxors like BaTi_0.65 Zr_0.35O₃ (BTZ35).

Keywords:

• Relaxor ferroelectrics
• random fields
• polar nanoregions
• dynamic criticality
• superdipolar glass
• percolation
• interfacial creep
• segmental relaxation

Disclosure statement

No potential conflict of interest was reported by the author.