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Electric field dependences of Curie and Néel phase transition temperatures in magnetoelectric relaxor multiferroic Pb(Fe 0.5 Ta 0.5 )O 3 crystals seen via acoustic emission
Author(s) -
Dul'kin Evgeniy,
Gruszka Irena,
Kania Antoni,
Roth Michael
Publication year - 2016
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.201552668
Subject(s) - condensed matter physics , materials science , tetragonal crystal system , ferroelectricity , electric field , multiferroics , antiferromagnetism , curie temperature , phase transition , monoclinic crystal system , curie–weiss law , phase (matter) , ferromagnetism , physics , dielectric , crystal structure , crystallography , chemistry , optoelectronics , quantum mechanics
Pb(Fe 0.5 Ta 0.5 )O 3 magnetic and ferroelectric relaxor multiferroic crystals have been studied under both temperature and dc external electric field conditions by means of acoustic emission technique. All the characteristic relaxor points as Burns T d ≈ 610 K and intermediate T* ≈ 500 K temperatures, as well as both Curie ferroelectric cubic‐tetragonal T c 1 ≈ 259 K and tetragonal–monoclinic T c 2 ≈ 201 K structural and Néel antiferromagnetic–paramagnetic T N ≈ 187 K phase transitions have been successfully detected. It is shown that, when an external dc electric field is applied, both T c 1 and T c 2 exhibit a nonlinear or V‐shape behavior and attain the sharp minima at threshold temperatures T th 1 ≈ 247 K and T th 2 ≈ 200 K with the threshold field E th ≈ 0.1 kV cm −1 , as the field enhances, while their acoustic emission count rate monotonically increases. It is shown, too, that the T N behaves linearly in dependence on dc electric field with a negative slope of about −20 K cm kV −1 , while its acoustic emission count rate monotonically decreases. All these data are discussed from a viewpoint of presence of polar nanoregions and magnetoelectric coupling effect in Pb(Fe 0.5 Ta 0.5 )O 3 crystals.