Modeling of polar clusters in disordered perovskites: the S-K model with tunneling

• Type: Article in International Scientific Journal
• Date: 2000

Authors

Almeida, BG (Author) Other; Lacerda Aroso, MT (Author) Other; Ribeiro, JL (Author) Other; Chaves, MR (Author) FCUP; Almeida, A (Author) FCUP

Journal

Title: Ferroelectrics

Vol. 239

Pages: 1075-1082

ISSN: 0015-0193

Publisher: Taylor & Francis

Indexing

ISI Web of Knowledge - 1 Citation

Scopus - 0 Citations

Other information

Authenticus ID: P-001-1GA

Abstract (EN): The polar clusters generated by random non-central impurities in quantum paraelectrics determine to a great extent the complex dielectric behaviour observed in systems like SCT, KTN or KTL. The competition between a quantum paraelectric phase and an impurity-driven ferroelectric or glass phase depends on the concentration and on the nature of the interaction between clusters. This work presents a simple model in which each cluster is represented by a quantum two level system involving an effective Ising dipolar moment eta and a tunneling energy A. The interactions between clusters are taken into account by following the guide-lines of the Sherrington-Kirkpatrick model for spin glasses. General expressions for the polarization (P) and the Edwards-Anderson order parameter (q) are given and the phase diagram involving temperature, the normalized mean interaction energy J(0)/J and tunneling energy A/J(0) is built.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 8