Multi elements substituted Aurivillius phase relaxor ferroelectrics using high entropy design concept

Materials & Design

Haixue Yan¹  Yajun Yue²  Matteo Palma²  Xinzhao Xu²  Man Zhang³  Michael J. Reece³ 

[1] Corresponding author.;School of Biological and Chemical Sciences, Institute of Bioengineering, and Materials Research Institute, Queen Mary University of London, Mile End Road, London E1 4NS, UK;School of Engineering and Materials Science, Queen Mary University of London, Mile End Road, London E1 4NS, UK;

关键词: High entropy;    Aurivillius phase;    Relaxor ferroelectric;    Domain;    Nano domains;   

DOI  :  

来源: DOAJ

【 摘 要 】

The concept of high entropy ceramics opens up the possibility to optimise the properties of relaxor ferroelectrics with Aurivilius phase structures. In this paper, two new multi-element substituted Aurivillius phase ceramics, (Ca0.25Sr0.25Ba0.25Pb0.25)Bi2Nb2O9 and (Ca0.2Sr0.2Ba0.2Pb0.2Nd0.1Na0.1)Bi2Nb2O9 are prepared. Both ceramics are single phase, exhibiting orthorhombic symmetry with space group A21am at room temperature. The frequency dependence of the temperature of the dielectric permittivity peak, Tm, shows relaxor behaviour for both ceramics. Multi-domain configurations, including long range ordered ferroelectric domains and nano domains, were observed using piezoresponse force microscopy (PFM). Under an applied DC field, the nano domains irreversibly transformed to micro-meter sized domains, which is consistent with the Vogel-Fulcher Law fitted results that show that the freezing temperatures of the two ceramics are above room temperature. Their improved piezoelectric constant is attributed to their low coercive fields, which are related to the multi domain configurations in the Aurivillius phase relaxor ferroelectrics.

【 授权许可】

Unknown