DOCSLIB.ORG

Novel Tetragonal-Like Phases of Bifeo3 Films Grown by Pulsed Laser Deposition, and Their Characterisation

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Novel Tetragonal-Like Phases of Bifeo3 Films Grown by Pulsed Laser Deposition, and Their Characterisation Novel Tetragonal-Like Phases of BiFeO3 Films Grown by Pulsed Laser Deposition, and their Characterisation Thomas C. Young A thesis in fulfilment of the requirements for the degree of Master of Science The University of New South Wales Faculty of Science School of Materials Science and Engineering August 2019 Surname/Family Name : Young Given Name/s : Thomas Abbreviation for degree as give in the : Master of Science (MSc) University calendar Faculty : Science School : Materials Science and Engineering Novel Tetragonal-Like Phases of BiFeO Films Grown by Thesis Title : 3 Pulsed Laser Deposition, and their Characterisation Abstract 350 words maximum: (PLEASE TYPE) This thesis presents an experimental study of multiferroic BiFeO3 thin films grown by pulsed laser deposition. Multiferroics – materials which possess two or more ferroic orders (most commonly ferroelectricity and magnetic order) – offer opportunities for novel devices in data storage and spintronics. Bismuth ferrite (BiFeO3 – BFO) is the only known room-temperature multiferroic, making it attractive for practical applications. This study considers the range of growth parameters available during pulsed laser deposition and their role in tuning the structure of so called ‘T’ phase’ BiFeO3 thin films, grown on (001) LaAlO3 substrates. To gain insight into the influence of growth parameters on the physical properties of the films, structural, electrical and magnetic characterisation was performed. X-ray diffraction techniques including 2θ-ω coupled scans, X-ray reflectivity (XRR) and reciprocal space mapping (RSM), along with transmission electron microscopy (TEM), were used for structural and chemical characterisation. Advanced modes of scanning probe microscopy (SPM) were used to probe surface quality, ferroelectric properties, and magnetic response of the films. It was found that by using growth conditions to modify film stoichiometry and structure in localised nano- regions, it was possible to stabilise the highly elongated out of plane T’ phase with high crystallinity and coherence to thicknesses up to 73 nm, far beyond the previously-reported ‘critical thickness’ of ~25 nm. It was also found that 2% cobalt doping on thick T’ phase BFO films had a negligible influence on the structural, electronic and magnetic properties; however the cobalt doping yielded films with functional response such as conductive domain walls. The results presented here provide new ways to probe the properties of ‘pure’ T’ phase BFO and demonstrate that by carefully controlling growth conditions, one can tailor structural parameters, phase fractions, and in turn the functional response of multiferroic thin films. Declaration relating to disposition of project thesis/dissertation I hereby grant to the University of New South Wales or its agents the right to archive and to make available my thesis or dissertation in whole or in part in the University libraries in all forms of media, now or here after known, subject to the provisions of the Copyright Act 1968. I retain all property rights, such as patent rights. I also retain the right to use in future works (such as articles or books) all or part of this thesis or dissertation. I also authorise University Microfilms to use the 350 word abstract of my thesis in Dissertation Abstracts International (this is applicable to doctoral theses only). …………………………………… ……………………………………..……………… ……….……………………...…….… Signature Witness Signature Date The University recognises that there may be exceptional circumstances requiring restrictions on copying or conditions on use. Requests for restriction for a period of up to 2 years must be made in writing. Requests for a longer period of restriction may be considered in exceptional circumstances and require the approval of the Dean of Graduate Research. FOR OFFICE USE Date of completion of requirements ONLY for Award: i ORIGINALITY STATEMENT ‘I hereby declare that this submission is my own work and to the best of my knowledge it contains no materials previously published or written by another person, or substantial proportions of material which have been accepted for the award of any other degree or diploma at UNSW or any other educational institution, except where due acknowledgement is made in the thesis. Any contribution made to the research by others, with whom I have worked at UNSW or elsewhere, is explicitly acknowledged in the thesis. I also declare that the intellectual content of this thesis is the product of my own work, except to the extent that assistance from others in the project's design and conception or in style, presentation and linguistic expression is acknowledged.’ Signed …………………………………………….............. Date …………………………………………….............. ii INCLUSION OF PUBLICATIONS STATEMENT UNSW is supportive of candidates publishing their research results during their candidature as detailed in the UNSW Thesis Examination Procedure. Publications can be used in their thesis in lieu of a Chapter if: • The student contributed greater than 50% of the content in the publication and is the “primary author”, ie. the student was responsible primarily for the planning, execution and preparation of the work for publication • The student has approval to include the publication in their thesis in lieu of a Chapter from their supervisor and Postgraduate Coordinator. • The publication is not subject to any obligations or contractual agreements with a third party that would constrain its inclusion in the thesis Please indicate whether this thesis contains published material or not. This thesis contains no publications, either published or submitted for ☐ publication Some of the work described in this thesis has been published and it has ☒ been documented in the relevant Chapters with acknowledgement This thesis has publications (either published or submitted for ☐ publication) incorporated into it in lieu of a chapter and the details are presented below CANDIDATE’S DECLARATION I declare that: • I have complied with the Thesis Examination Procedure • where I have used a publication in lieu of a Chapter, the listed publication(s) below meet(s) the requirements to be included in the thesis. Name Thomas Young Signature Date (dd/mm/yy) iii COPYRIGHT STATEMENT ‘I hereby grant the University of New South Wales or its agents the right to archive and to make available my thesis or dissertation in whole or part in the University libraries in all forms of media, now or here after known, subject to the provisions of the Copyright Act 1968. I retain all proprietary rights, such as patent rights. I also retain the right to use in future works (such as articles or books) all or part of this thesis or dissertation. I also authorise University Microfilms to use the 350 word abstract of my thesis in Dissertation Abstract International (this is applicable to doctoral theses only). I have either used no substantial portions of copyright material in my thesis or I have obtained permission to use copyright material; where permission has not been granted I have applied/will apply for a partial restriction of the digital copy of my thesis or dissertation.' Signed ……………………………………………........................... Date ……………………………………………........................... AUTHENTICITY STATEMENT ‘I certify that the Library deposit digital copy is a direct equivalent of the final officially approved version of my thesis. No emendation of content has occurred and if there are any minor variations in formatting, they are the result of the conversion to digital format.’ Signed ……………………………………………........................... Date ……………………………………………........................... iv Acknowledgements A special thanks to my grandfather who fostered my interest in science from a young age and always encouraged me to follow my curiosity, you will be greatly missed. To everyone who helped make this thesis possible. I would not have been able to make it this far without all the support you have given me. v Abstract This thesis presents an experimental study of multiferroic BiFeO3 thin films grown by pulsed laser deposition. Multiferroics – materials which possess two or more ferroic orders (most commonly ferroelectricity and magnetic order) – offer opportunities for novel devices in data storage and spintronics. Bismuth ferrite (BiFeO3 – BFO) is the only known room-temperature multiferroic, making it attractive for practical applications. This study considers the range of growth parameters available during pulsed laser deposition and their role in tuning the structure of so called ‘T’ phase’ BiFeO3 thin films, grown on (001) LaAlO3 substrates. To gain insight into the influence of growth parameters on the physical properties of the films, structural, electrical and magnetic characterisation was performed. X-ray diffraction techniques including 2θ-ω coupled scans, X-ray reflectivity (XRR) and reciprocal space mapping (RSM), along with transmission electron microscopy (TEM), were used for structural and chemical characterisation. Advanced modes of scanning probe microscopy (SPM) were used to probe surface quality, ferroelectric properties, and magnetic response of the films. It was found that by using growth conditions to modify film stoichiometry and structure in localised nano-regions, it was possible to stabilise the highly elongated out of plane T’ phase with high crystallinity and coherence to thicknesses up to 73 nm, far beyond the previously-reported ‘critical thickness’ of ~25 nm. It was also found that 2% cobalt doping on thick T’ phase BFO films had a negligible influence
Load more

Recommended publications
  • A Structural Study of Bifeo3 – Pbtio3 Thin Films Deposited by Pulsed Laser Deposition
    A Structural Study of BiFeO3 – PbTiO3 Thin Films Deposited by Pulsed Laser Deposition Faye Bygrave Submitted in accordance with the requirements for the degree of Doctor of Philosophy The University of Leeds Institute for Materials Research School of Process, Environmental and Materials Engineering September, 2011 ~ ii ~ The candidate confirms that the work submitted is her own and that appropriate credit has been given where reference has been made to the work of others. This copy has been supplied on the understanding that it is copyright material and that no quotation from the thesis may be published without proper acknowledgement. The right of Faye Bygrave to be identified as Author of this work has been asserted by her in accordance with the Copyright, Designs and Patents Act 1988. © 2011 The University of Leeds and Faye Bygrave. ~ iii ~ To my four ladies In memory of my Granny “If it was easy everyone would do it” Mum ~ iv ~ Acknowledgements Firstly I would like to express my deepest thanks to Prof. Andrew Bell for all the support, guidance and advice in all aspects of this project over the past four years. He has been invaluable throughout this whole endeavour, without him this work could never have been realised or have been such fun. I would also like to thank Dr. Tim Comyn for all his support and encouraging words. This work would not have been possible if it were not for his technical expertise and efforts in the x-ray diffraction facility for the entire department. I have been very fortunate to work with the supervision of such outstanding and inspiring people.
    [Show full text]
  • Ferroelectric and Dielectric Investigations of Bismuth Ferrite (Bifeo 3) Nanoceramics
    Available online a t www.scholarsresearchlibrary.com Scholars research library Archives of Applied Science Research, 2011, 3 (5):384-389 (http://scholarsresearchlibrary.com/archive.html) ISSN 0975-508X CODEN (USA) AASRC9 Ferroelectric and Dielectric Investigations of Bismuth Ferrite (BiFeO 3) Nanoceramics Chandrashekhar P. Bhole Government Polytechnic, Khamgaon, Buldhana Maharashtra (India) __________________________________________________________________ ABSTRACT In this paper we report the synthesis of BiFeO 3 ceramics by solid state reaction method. The X- ray analysis depicts the BiFeO 3 sample have rhombhohedral perovskite structure. The ferroelectric measurement shows BiFeO 3 ceramic exhibits ferroelectric nature with saturation, 2 2 remnant polarizations of P s = 0.26 µC/cm , P r = 0.11 µC/cm respectively. The dielectric constant and loss as a function of temperature (30-325 oC) in the frequency range 10 kHz-1MHz shows that the dielectric constant and loss increases with increasing temperature. The room temperature dielectric measurement with frequency reveals the dielectric constant and loss decreases with increasing frequency for BiFeO 3 ceramics. Keywords: BiFeO 3 Ceramics, Solid State Reaction, Characterizations, Measurements. __________________________________________________________________ INTRODUCTION Multiferroic materials possess simultaneous existence of electric and magnetic nature together in a single phase [1-2]. These multiferroics have potential applications in information storage [3], microelectronics [4], memories,
    [Show full text]
  • Bismuth Ferrite Materials for Solar Cells: Current Status and Prospects
    Bismuth ferrite materials for solar cells: Current status and prospects Guang Chena, Jian Chena, Weijie Peia, Yinmei Lua, Qingfeng Zhanga,*, Qi Zhangb, Yunbin Hea,* a Key Lab of Ferro & Piezoelectric Materials and Devices, Ministry of Education Key Laboratory of Green Preparation and Application for Functional Materials, School of Materials Science & Engineering, Hubei University, Wuhan, 430062, China b Department of Manufacturing and Materials, Cranfield University, Cranfield, Bedfordshire, MK43 0AL, UK Abstract Different from classical semiconductor photovoltaic devices, for ferroelectric photovoltaic devices, the open-circuit voltage (Voc) can be four and even more orders of magnitude larger than the band gap of the ferroelectric, and the built-in electric field arising from the remnant polarization of the ferroelectric is throughout the bulk region, which is good for obtaining giant power conversion efficiency. Among ferroelectric materials, BiFeO3 with remnant polarization of as high as -100 μC/cm2 has the narrowest direct band gap (-2.7 eV). These indicate that high power conversion efficiency may be obtained in BiFeO3-based photovoltaic devices. Also, some significant research results about photovoltaic effects of BiFeO3 materials have been recently acquired. In order to better promote the development of BiFeO3-based photovoltaic devices, in this paper, we present a comprehensive review on the latest research progress in photovoltaic effects of BiFeO3 materials with different kinds of topography, including bulk, thin film, and nanomaterials. Keywords: BiFeO3 materials Narrow band gap Large remnant polarization Built-in electric field Ferroelectric photovoltaic effect 1. Introduction With the increasing global energy crisis and environmental issues, the development of clean and sustainable energy has become a major issue that governments need to address urgently in the worldwide.
    [Show full text]
  • Multifunctional Bismuth Ferrite Nanomaterials As a New‑Generation Catalyst for Water Treatment
    This document is downloaded from DR‑NTU (https://dr.ntu.edu.sg) Nanyang Technological University, Singapore. Multifunctional bismuth ferrite nanomaterials as a new‑generation catalyst for water treatment Hu, Zhong Ting 2017 Hu, Z. T. (2017). Multifunctional bismuth ferrite nanomaterials as a new‑generation catalyst for water treatment. Doctoral thesis, Nanyang Technological University, Singapore. http://hdl.handle.net/10356/69460 https://doi.org/10.32657/10356/69460 Downloaded on 24 Sep 2021 02:23:24 SGT MULTIFUNCTIONAL BISMUTH FERRITE NANOMATERIALS AS A NEW-GENERATION CATALYST FOR WATER TREATMENT HU ZHONG TING SCHOOL OF CIVIL AND ENVIRONMENTAL ENGINEERING 2017 MULTIFUNCTIONAL BISMUTH FERRITE NANOMATERIALS AS A NEW-GENERATION CATALYST FOR WATER TREATMENT HU ZHONG TING School of Civil and Environmental Engineering A thesis submitted to the Nanyang Technological University in partial fulfillment of the requirement for the degree of Doctor of Philosophy 2017 Acknowledgements First and foremost, I would like to express my sincere gratitude to my respected supervisor, Associate Prof. Lim Teik Thye, for his invaluable advices and patient guidances. He always encourages me to have high aspiration and strive for excellence. I am eternally indebted to my beloved wife (Xu Wen Jin), parents, grandparents, sister/brother-in-law, uncles, and aunts, for their unconditional love, unselfish devotion, and unwavering support. I would like to give very special thanks to my uncle, Prof. Chen Jianfeng, who guides me forward and along the right paths concurrently. I would like to thank many friends for their help and support. My special thanks to the members of Prof. Lim’s group, Dr. Goei Ronn, Dr.
    [Show full text]
  • Synthesis of Bismuth Ferrite for Photoelectrochemical Water Splitting
    Graduate Theses, Dissertations, and Problem Reports 2017 Synthesis of Bismuth Ferrite for Photoelectrochemical Water Splitting Fagr Albagle Follow this and additional works at: https://researchrepository.wvu.edu/etd Recommended Citation Albagle, Fagr, "Synthesis of Bismuth Ferrite for Photoelectrochemical Water Splitting" (2017). Graduate Theses, Dissertations, and Problem Reports. 5050. https://researchrepository.wvu.edu/etd/5050 This Thesis is protected by copyright and/or related rights. It has been brought to you by the The Research Repository @ WVU with permission from the rights-holder(s). You are free to use this Thesis in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you must obtain permission from the rights-holder(s) directly, unless additional rights are indicated by a Creative Commons license in the record and/ or on the work itself. This Thesis has been accepted for inclusion in WVU Graduate Theses, Dissertations, and Problem Reports collection by an authorized administrator of The Research Repository @ WVU. For more information, please contact [email protected]. Synthesis of Bismuth Ferrite for Photoelectrochemical Water Splitting Fagr Albagle Thesis submitted to the Benjamin M. Statler College of Engineering and Mineral Resources at West Virginia University in partial fulfillment of the requirements for the degree of Mechanical Engineering Master of Science in Mechanical Engineering Nianqiang Wu, Ph.D. Chair Konstantinos Sierros, Ph.D. Terence D. Musho, Ph.D. Department of Mechanical and Aerospace Engineering Morgantown, West Virginia 2017 Keywords: solar energy, photocatalysis, water splitting, hydrogen generation, photoelecrtochemical, bismuth ferrite oxide, semiconductor Copyright 2017 Fagr Albagle ABSTRACT Synthesis of Bismuth Ferrite for Photoelectrochemical Water Splitting by Fagr Albagle Converting solar energy to chemical fuels is one of the alternative solutions to address the sustainable energy challenges in the world.
    [Show full text]
  • Magnetic Properties of Bismuth Ferrite Nanopowder Obtained by Mechanochemical Synthesis I
    Vol. 126 (2014) ACTA PHYSICA POLONICA A No. 4 Proc. of the International Conference on Mechanochemistry and Mechanical Alloying, Kraków, Poland, June 2226, 2014 Magnetic Properties of Bismuth Ferrite Nanopowder Obtained by Mechanochemical Synthesis I. Szafraniak-Wizaa;*, B. Andrzejewskib and B. Hilczerb aInstitute of Materials Science and Engineering, Pozna« University of Technology, pl. M. Skªodowskiej-Curie 5, 60-965 Pozna«, Poland bInstitute of Molecular Physics, PAS, M. Smoluchowskiego 17, 60-179 Pozna«, Poland Multiferroic bismuth ferrite (BiFeO3) nanopowders have been obtained at room temperature by mechanochem- ical synthesis. Depending on the post-synthesis processing the nanopowders exhibited dierences in the mean sizes, presence of amorphous layer and/or secondary phases. Extended magnetic study performed for fresh, annealed and hot-pressed nanopowders revealed substantial improvement of the magnetic properties in the as-prepared powder. DOI: 10.12693/APhysPolA.126.1029 PACS: 81.07.Bc, 81.07.Wx, 81.20.Ev, 75.85.+t 1. Introduction 2. Experimental Multiferroics exhibit at least two primary ferroic or- Bismuth ferrite nanopowder was synthesized by ders: ferroelectric, ferromagnetic, ferroelastic or ferrotor- mechanochemical route. Details of synthesis were pub- roic in a single homogeneous phase and the order param- lished in previous paper [7]. Commercially available ox- eters can be mutually coupled [1]. Especially interest- ides (Bi2O3 and Fe2O3 purchased from Aldrich, 99% pu- ing are ferroelectromagnets (or magnetoelectric multifer- rity) in stoichiometric ratio were milled in a SPEX 8000 roics) having magnetization and dielectric polarization, Mixer Mill for 120 h. The thermal treatment was per- which can be modulated and activated by an external formed for 1 h in air atmosphere under atmospheric pres- electric eld and magnetic eld, respectively.
    [Show full text]
  • Study on Structural/Magnetic Properties Correlation of Multiferroic Perovskite Bismuth Ferrite (Bifeo3)
    Int. J. New. Hor. Phys. 7, No. 1, 31-36 (2020) 31 International Journal of New Horizons in Physics http://dx.doi.org/10.18576/ijnhp/070105 Study on Structural/Magnetic Properties Correlation of Multiferroic Perovskite Bismuth Ferrite (BiFeO3) M. I. Marzouk1, H. M. Hashem1, S. Soltan1,2 and A. A. Ramadan1 1Department of physics, Faculty of Science, Helwan university, Cairo, Egypt. 2Max- Planck institute for solid state research, Stuttgart, Germany. Received:21 Oct. 2019,Revised: 22 Nov.2019,Accepted:24 Dec.2019. Publishedonline:1 Jan 2020. Abstract: The structural characterization and magnetic investigations of perovskite bismuth ferrite were studied using X- ray diffraction (XRD) and superconducting quantum interference device (SQUID) magnetometer, respectively. Raman spectroscopy investigation was performed in order to confirm the obtaining of bismuth ferrite (BiFeO3) structural phase. The optimum conditions for the synthesis of bismuth ferrite sample was found to be 600 oC and 800 oC /6 hours for the first and second sintering stage, respectively. The sample has been melted as sintering temperature ascended above of 800 oC. Rietveld refinement was applied for quantitative phase analysis. The Neel temperature of bismuth ferrite was 538 K as determined from the electrical resistivity measurement as a function of temperature. A magnetic phase transition from metallic (Para magnetic) into insulator (Anti ferromagnetic) state was observed at the Neel temperature. A room temperature weak ferromagnetic behaviour is observed in BiFeO3 (BFO) sample that is referred to the spin canting configuration. Keywords: Structural, Magnetic, Bismuth Ferrite. 1 Introduction the ferroelectric distortion that appears in the perovskite structure, which then leads toa switching of magnetization Bismuth ferrite or bismuth iron oxide (BiFeO3) is a through spin canting as reported by Ederer and Fennie [5].
    [Show full text]
  • Structural Phase Relations in Perovskite-Structured Bifeo3-Based Multiferroic Compounds
    Journal of Advanced Ceramics 2013, 2(2): 103–111 DOI: 10.1007/s40145-013-0052-2 ISSN 2226-4108 Review Structural phase relations in perovskite-structured BiFeO3-based multiferroic compounds Valdirlei Fernandes FREITAS*, Gustavo Sanguino DIAS, Otávio Algusto PROTZEK, Diogo Zampieri MONTANHER, Igor Barbosa CATELLANI, Daniel Matos SILVA, Luiz Fernando CÓTICA, Ivair Aparecido dos SANTOS UEM—Universidade Estadual de Maringá, GDDM—Grupo de Desenvolvimento de Dispositivos Multifuncionais, Departamento de Física, Maringá, Brazil Received: January 16, 2013; Revised: March 01, 2013; Accepted: March 02, 2013 ©The Author(s) 2013. This article is published with open access at Springerlink.com Abstract: In this review, the state of the art in understanding the structural phase relations in perovskite-structured BiFeO3-based polycrystalline solid solutions is presented and discussed. Issues about the close relation between the structural phase and overall physical properties of the reviewed systems are pointed out and discussed. It is shown that, by adjusting the structural symmetric arrangement, the ferroelectric and magnetic properties of BiFeO3-based polycrystalline solid solutions can be tuned to find specific multifunctional applications. However, an intrinsic mechanism linking structural arrangement and physical properties cannot be identified, revealing that this subject still deserves further discussion and investigation. Keywords: bismuth ferrite; ferroelectrics; multiferroics smart devices. In fact, compounds with perovskite structure may have more than one applicable 1 Introduction property (e.g., ferroelectricity, (weak, ferri) magnetism, piezoelectricity, and magnetoelectric coupling) to be Multifunctional compounds are materials whose two classified as multifunctional. Furthermore, materials or more physical properties can be exploited with perovskite structure that present ferroelectricity, simultaneously or separately for the same or different ferroelasticity and/or some magnetic order purposes.
    [Show full text]
  • A Facile Synthesis and Characterization of Highly Crystalline Submicro-Sized Bifeo3
    materials Article A Facile Synthesis and Characterization of Highly Crystalline Submicro-Sized BiFeO3 Dovydas Karoblis 1, Diana Griesiute 1, Kestutis Mazeika 2, Dalis Baltrunas 2, Dmitry V. Karpinsky 3 , Anna Lukowiak 4, Pawel Gluchowski 4,5 , Rimantas Raudonis 1, Arturas Katelnikovas 1 , Aleksej Zarkov 1 and Aivaras Kareiva 1,* 1 Institute of Chemistry, Vilnius University, Naugarduko 24, LT-03225 Vilnius, Lithuania; [email protected] (D.K.); [email protected] (D.G.); [email protected] (R.R.); [email protected] (A.K.); [email protected] (A.Z.) 2 Center for Physical Sciences and Technology, LT-02300 Vilnius, Lithuania; kestas@ar.fi.lt (K.M.); dalis@ar.fi.lt (D.B.) 3 Scientific-Practical Materials Research Centre of NAS of Belarus, 220072 Minsk, Belarus; [email protected] 4 Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okolna 2, PL 50422 Wroclaw, Poland; [email protected] (A.L.); [email protected] (P.G.) 5 Nanoceramics Inc., Okolna 2, PL-50422 Wroclaw, Poland * Correspondence: [email protected] Received: 17 June 2020; Accepted: 4 July 2020; Published: 7 July 2020 Abstract: In this study, a highly crystalline bismuth ferrite (BFO) powder was synthesized using a novel, very simple, and cost-effective synthetic approach. It was demonstrated that the optimal annealing temperature for the preparation of highly-pure BFO is 650 ◦C. At lower or higher temperatures, the formation of neighboring crystal phases was observed. The thermal behavior of BFO precursor gel was investigated by thermogravimetric and differential scanning calorimetry (TG-DSC) measurements.
    [Show full text]
  • Pr and Gd Co-Doped Bismuth Ferrite Thin Films with Enhanced
    Bull. Mater. Sci., Vol. 37, No. 7, December 2014, pp. 1725–1729. c Indian Academy of Sciences. Pr and Gd co-doped bismuth ferrite thin films with enhanced multiferroic properties CHANG CHUN CHEN∗, ZI XUAN LIU, GUI WANG and YI LIN YAN College of Materials Science and Engineering, Nanjing University of Technology, No. 5 Xinmofan Road, Nanjing 210009, China MS received 21 October 2013; revised 25 January 2014 Abstract. Pr and Gd co-modified Bi0·95−xPrx Gd0·05FeO3 (x = 0·00, 0·05, 0·10) (BPGFO) thin films on Pt(111)/ Ti/SiO2/Si(100) substrates were prepared by a sol-gel together with spin coating technique. A detailed study of elec- trical and magnetic properties of these thin films is reported. X-ray diffraction analysis shows that, with an increase in Pr content, the crystal structures of BPGFO thin films retain rhombohedral (R3c) symmetry accompanied by structure distortion. Polarization-electric field hysteresis loops of these thin films demonstrate that the incorporation of Pr and Gd into the Bi site of BiFeO3 thin film could enhance the ferroelectric performance. Compared to other thin films, the optimal ferroelectric behaviours in Bi0·85Pr0·1Gd0·05FeO3 thin film are ascribed to its large dielectric constant, low dissipation factor and low leakage current density. Room temperature magnetization-magnetic field curves of these thin films indicate that all the samples are of paramagnetic behaviours and the enhanced saturation magnetic properties can be found. Keywords. Pr and Gd co-modified BiFeO3 thin film; ferroelectric properties; sol-gel. 1. Introduction partial ionic substitution to Bi1−xAxFeO3 (A is a lanthanide ion, rare earth metal) or to BiFe1−xMxO3 (M is another 3d In recent years, great attention has been paid to single- transition metal) is a promising way for upgrading multi- phase BiFeO3 (BFO) multiferroic materials crystallized in ferroics properties (Lee et al 2006; Takeshi Kawae et al the ABO3-type perovskite structure with the R3c space group 2008).
    [Show full text]
  • The Use of Visible Light Absorbing Bismuth-Containing Semiconductors As Heterogeneous Photocatalysts for Selective Chemical Transformations
    The Use of Visible Light Absorbing Bismuth-Containing Semiconductors as Heterogeneous Photocatalysts for Selective Chemical Transformations Christopher Adam Unsworth Doctor of Philosophy University of York Chemistry August 2017 Abstract Bismuth-containing semiconducting materials were used as visible light absorbing heterogeneous photocatalysts for selective chemical transformations. The work demonstrates the importance of kinetic control in achieving selectivity; either through photocatalyst inhibition or through the presence of reagents capable of fast reactions with known intermediates. Bismuth oxide (β-Bi2O3), bismuth ferrite (BiFeO3), bismuth tungstate microflowers (Bi2WO6) and bismuth vanadate nanoparticles (nan-BiVO4) were synthesised and characterised by PXRD, SEM, DRUVS and BET. The bismuth-containing oxides were compared as photocatalysts for the aerobic oxidation of benzyl alcohol. The highest benzyl alcohol conversion (88%) and benzaldehyde selectivity (95%) was achieved with the use of nan-BiVO4. Further modifications to nan-BiVO4 resulted in materials that were less active for selective benzyl alcohol oxidation than unmodified nan-BiVO4. Further study of nan-BiVO4 as a heterogeneous photocatalysts for the selective oxidation of para-substituted benzyl alcohols was carried out. It was found that alcohol conversions and aldehyde selectivities were affected by by-product inhibition. The addition of 1 mol% 4-methoxybenzoic acid significantly reduced 4-methoxybenzyl alcohol conversion (to 49%). Isotopically labelled benzyl alcohols were used to show that α C-H bond cleavage was not rate limiting. However, changes in charge carrier lifetimes observed using TRPLS suggested that the charge carriers associated to the lifetimes observed were relevant to benzyl alcohol oxidation. Bismuth-containing semiconductors were also investigated as trifluoromethylation heterogeneous photocatalysts. Nan-BiVO4 was capable of oxytrifluoromethylation of styrene via the reduction of Umemoto’s reagents.
    [Show full text]
  • Laser Fragmentation Synthesis of Colloidal Bismuth Ferrite Particles
    nanomaterials Article Laser Fragmentation Synthesis of Colloidal Bismuth Ferrite Particles Simon Siebeneicher 1 , Friedrich Waag 1, Marianela Escobar Castillo 2, Vladimir V. Shvartsman 2 , Doru C. Lupascu 2 and Bilal Gökce 1,* 1 Technical Chemistry I and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Universitaetsstr. 7, 45141 Essen, Germany; [email protected] (S.S.); [email protected] (F.W.) 2 Institute for Materials Science and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, 45141 Essen, Germany; [email protected] (M.E.C.); [email protected] (V.V.S.); [email protected] (D.C.L.) * Correspondence: [email protected] Received: 8 January 2020; Accepted: 13 February 2020; Published: 19 February 2020 Abstract: Laser fragmentation of colloidal submicron-sized bismuth ferrite particles was performed by irradiating a liquid jet to synthesize bismuth ferrite nanoparticles. This treatment achieved a size reduction from 450 nm to below 10 nm. A circular and an elliptical fluid jet were compared to control the energy distribution within the fluid jet and thereby the product size distribution and educt decomposition. The resulting colloids were analysed via UV-VIS, XRD and TEM. All methods were used to gain information on size distribution, material morphology and composition. It was found that using an elliptical liquid jet during the laser fragmentation leads to a slightly smaller and narrower size distribution of the resulting product compared to the circular jet. Keywords: nanoparticles; size reduction; picosecond; ray tracing; multiferroic 1. Introduction The perovskite bismuth ferrite (BFO) unites several interesting material properties and attracts strong research interest as a multiferroic material [1,2].
    [Show full text]