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A Novel Room‐Temperature Multiferroic System of Hexagonal Lu 1− x In x FeO 3
Author(s) -
Liu Juan,
Sun Tu Lai,
Liu Xiao Qiang,
Tian He,
Gao Ting Ting,
Chen Xiang Ming
Publication year - 2018
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201706062
Subject(s) - materials science , antiferromagnetism , ferroelectricity , multiferroics , curie temperature , crystallography , ferromagnetism , condensed matter physics , phase transition , paramagnetism , dielectric , chemistry , physics , optoelectronics
In the present work, h‐RFeO 3 multiferroic ceramics are designed and created by introducing chemical pressure (In‐substitution for Lu) in LuFeO 3 . Lu 1− x In x FeO 3 ( x = 0‐0.75) ceramics are prepared by the standard solid‐state reaction process. The crystal structure of the present ceramics is tuned from centrosymmetric Pbnm ( x = 0) to non‐centrosymmetric P6 3 cm ( x = 0.4–0.6), and subsequently to centrosymmetric P6 3 /mmc ( x = 0.75), while the Pbnm and P6 3 cm biphase structure is detected for x = 0.25. The Curie temperature for the polar P6 3 cm ( x = 0.4–0.6) phase decreases from >1000 to ≈550 K with increasing x . Cloverleaf ferroelectric domain structures are determined in polar Lu 0.5 In 0.5 FeO 3 samples, and the ferroelectric domain walls at atomic scale are evaluated by the aberration‐corrected high‐angle annular dark‐field scanning transmission electron microscopy (HAADF STEM), where the spontaneous polarization of 1.73 µC cm −2 is determined for x = 0.5. The spontaneous polarization is also confirmed by calculating the site displacement from the centrosymmetric phase based on the X‐ray diffraction (XRD) data. Meanwhile, two magnetic transitions are determined for all compositions, that is, paramagnetic to antiferromagnetic transition at Néel temperature T N (≈350 K for x = 0.4–0.6), and antiferromagnetic to weak‐ferromagnetic transition at spin‐reorientation temperature T SR . The co‐presence of ferroelectric and antiferromagnetic orders confirms the present ceramics as promising room‐temperature multiferroic materials.