Crystal chemistry and magnetic properties of Gd-substituted Aurivillius-type Bi5FeTi3O15 ceramics

DOI: 10.1021/acs.jpcc.8b03801

Authors: Vladimir Koval (Slovak Academy of Sciences) , Ivan Skorvanek (Slovak Academy of Sciences) , Giuseppe Viola (Queen Mary, University of London) , Man Zhang (Queen Mary, University of London) , Chenglong Jia (Lanzhou University) , Haixue Yan (Queen Mary, University of London)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: The Journal Of Physical Chemistry C

State: Published (Approved)
Published: June 2018
Diamond Proposal Number(s): 16332

Abstract: Aurivillius-phase ferroelectrics with high Curie temperature can be turned into multiferroic materials by incorporating magnetic ions. The four-layer Aurivillius-type system Bi5FeTi3O15 is well known to show a strong magnetoelectric effect; however, much controversy exists on its magnetic state and possible multiferroicity at room temperature. In this paper, we report on a detailed investigation on the interconnections between crystal chemistry and magnetic properties of Bi5FeTi3O15 ceramics chemically modified by the A-site gadolinium substitution. The structural studies showed that all Bi5-xGdxFeTi3O15 (0 ≦ x ≦ 1) samples adopt the polar orthorhombic space group symmetry A21am at room temperature. The unit cell volume and the orthorhombic distortion decrease alongside the reduction of octahedral tilts with increasing amount of Gd added. The decrease in tilting distortion of [Ti/Fe]O6 octahedra was further evidenced by the suppression of the Raman A1[111] tilt mode at 233 cm-1. By using the superconducting quantum interference device and vibrating sample magnetometry, it was demonstrated that all the ceramic series is paramagnetic from 5 K up to 700 K. It was thus concluded that the A-site substitution of Bi5FeTi3O15 with magnetic Gd ions brings about a slight structural relaxation of the parental orthorhombic lattice, but is not effective way to induce multiferroic properties in the Aurivillius compound. We suggest that the room-temperature (ferri/ferro/antiferro-) magnetism in Bi5FeTi3O15 previously reported in the literature might be due to the presence of magnetic impurities or local short-range magnetic ordering formed during material processing under different conditions.

Diamond Keywords: Ferroelectricity; Ferromagnetism

Subject Areas: Chemistry, Materials, Physics


Instruments: I15-Extreme Conditions

Other Facilities: P65 at PETRA III

Added On: 11/06/2018 08:45

Discipline Tags:

Quantum Materials Multiferroics Ceramics Physics Physical Chemistry Chemistry Magnetism Materials Science

Technical Tags:

Diffraction