Epitaxial Multiferroic BiFeO3 Thin Films: Progress and Future Directions

Chu, Y. H.,Martin, L. W.,Zhan, Q.,Yang, P. L.,Cruz, M. P.,Lee, K.,Barry, M.,Yang, S. Y.,Ramesh, R. Taylor Francis 2007 Ferroelectrics Vol.354 No.1

<P> We write this article in honor of Professor Vitaly L. Ginzburg, truly the father of the field of ferroelectricity. This article serves as a review of the current state of research pertaining to multiferroic BiFeO3 thin films. In this review we will delve into details of the growth of BiFeO3 thin films and the use of piezoforce microscopy and x-ray reciprocal space mapping to characterize the crystal structure and domain structure of BiFeO3. We will also discuss the use of vicinal and asymmetric substrates to simplify the domain structure in BiFeO3. By simplifying the domain structure we can, in turn, control the ferroelectric switching mechanisms in BiFeO3. Finally we describe the basic ferroelectric properties of BFO films and discuss the critical issues needed to be solved in BiFeO3 films including leakage, complex domain structure, coercivity, and reliability. Such results are promising for continued exploration for detailed multiferroic-coupling studies in the magnetoelectric BiFeO3 system and BiFeO3, in turn, provides a model platform with which to realize the exciting possibility of electrically control magnetism.</P>

The Magnetic Structural Analysis of Two-dimensional Triangular Heisenberg Antiferromagnetic Yb<SUB>0:42</SUB>Sc<SUB>0:58</SUB>FeO₃

Shin-ichiro Yano,Chin-Wei Wang 한국물리학회 2023 새물리 Vol.73 No.12

We report the magnetic structure of Yb<SUB>0:42</SUB>Sc<SUB>0:58</SUB>FeO₃ determined by powder neutron diffraction. The symmetry of the crystal structure is P6<SUB>3cm</SUB>. The magnetic structure was described by the linear combination of irreducible representations Γ<SUB>1</SUB> and Γ<SUB>2</SUB>. Two irreducible representations are necessary to describe the magnetic structures of two-dimensional Heisenberg antiferromagnets such as hexagonal-RMnO₃ and hexagonal-RFeO₃. The result is important in discussing the exchange parameters and the origin of the multiferroicity. We discuss possible ways to uniquely determine the magnetic structure and the origin of the multiferroicity of these systems.

반대칭 교환 상호작용을 갖도록 Fe-Site가 제어된 PbFe_1/2Nb_1/2O₃의 강유전/자기적 특성 연구

박지훈 ( Ji-hun Park ),이주현 ( Ju-hyeon Lee ),조재현 ( Jae-hyeon Cho ),장종문 ( Jong Moon Jang ),조욱 ( Wook Jo ) 한국전기전자재료학회 2022 전기전자재료학회논문지 Vol.35 No.3

We investigated the origin of magnetic behaviors induced by an asymmetric spin exchange interaction in Fe-site engineered lead iron niobate [Pb(Fe_1/2Nb_1/2)O₃, PFN], which exhibits a room-temperature multiferroicity. The magnitude of spin exchange interaction was regulated by the introduced transition metals with a distinct Bohr magneton, i.e., Cr, Co, and Ni. All compositions were found to have a single-phase perovskite structure keeping their ferroelectric order except for Cr introduction. We discovered that the incorporation of each transition metal imposes a distinct magnetic behavior on the lead iron niobate system; antiferro-, hard ferro-, and soft ferromagnetism for Cr, Co, and Ni, respectively. This indicates that orbital occupancy and interatomic distance play key roles in the determination of magnetic behavior rather than the magnitude of the individual Bohr magneton. Further investigations are planned, such as X-ray absorption spectroscopy, to clarify the origin of magnetic properties in this system.

Enhancement of photoresponse and photovoltaic properties in KBiFe2O5/BiFeO3 bilayer thin films

Subudhi Subhasri,Subramanyam B.V.R.S.,Alam Injamul,Mandal Manoranjan,Patra Santosini,Nayak Alok Kumar,Mahanandia Pitamber 한국물리학회 2024 Current Applied Physics Vol.64 No.-

In this report, the performance of a new photovoltaic device configuration in which bilayer KBiFe2O5 (KBFO)/BiFeO3 (BFO) as absorber materials have been investigated and compared with the single active layer-based devices of BFO and KBFO. The obtained short-circuit current density of 58.81 μAcm−2, open-circuit voltage of 0.65 V, and power conversion efficiency of 0.014 % for the complete photovoltaic device glass/FTO/KBFO/BFO/Ag are comparatively higher than that of glass/FTO/BFO/Ag and glass/FTO/KBFO/Ag devices. It has been observed that the active bilayer KBFO/BFO shows switchable photoresponse with respect to positive and negative polarities. This work may offer the procedures for further optimizing the photo absorber layer, thereby improving the performances of multiferroic-based devices for ferroelectric photovoltaic applications.

A Brief Review on Magnetoelectric Multiferroic Oxides

Cho, Jae-Hyeon,Jo, Wook The Korean Institute of Electrical and Electronic 2021 전기전자재료학회논문지 Vol.34 No.3

Magnetoelectric multiferroics, where a ferromagnetic and a ferroelectric order coexist and are coupled in a single phase, have been a hot topic in condensed matter physics for a long time owing to their ability to facilitate next-generation applications. In this review, we briefly introduce basic concept of the magnetoelectric multiferroic oxides as well as their history, physical origins, and significant achievements. The key moments contributing to the progress of magnetoelectric multiferroics are snapshotted chronologically, and then a discussion on the major magnetic exchange interactions and the ferroelectric origins are presented along with their coupling behavior. Furthermore, we argue a need for modifying the present classification of magnetoelectric multiferroics before presenting the evolution of multiferroics using representative examples with their properties such as magnetic/ferroelectric transition temperature, magnetization/electric polarization, and magnetoelectric coefficient. We hope that this brief review will provide the community researchers with insights into magnetoelectric multiferroic oxides.

A Brief Review on Magnetoelectric Multiferroic Oxides

조재현,조욱 한국전기전자재료학회 2021 전기전자재료학회논문지 Vol.34 No.3

Magnetoelectric multiferroics, where a ferromagnetic and a ferroelectric order coexist and are coupled in a single phase, have been a hot topic in condensed matter physics for a long time owing to their ability to facilitate nextgeneration applications. In this review, we briefly introduce basic concept of the magnetoelectric multiferroic oxides as well as their history, physical origins, and significant achievements. The key moments contributing to the progress of magnetoelectric multiferroics are snapshotted chronologically, and then a discussion on the major magnetic exchange interactions and the ferroelectric origins are presented along with their coupling behavior. Furthermore, we argue a need for modifying the present classification of magnetoelectric multiferroics before presenting the evolution of multiferroics using representative examples with their properties such as magnetic/ferroelectric transition temperature, magnetization/electric polarization, and magnetoelectric coefficient. We hope that this brief review will provide the community researchers with insights into magnetoelectric multiferroic oxides.

단일상 자기전기 다강성 산화물의 연구동향

조재현(Jae-Hyeon Cho),조욱(Wook Jo) 한국세라믹학회 2021 세라미스트 Vol.24 No.3

Magnetoelectric (ME) multiferroics manifesting the coexistence and the coupling of ferromagnetic and ferroelectric order are appealing widespread interest owing to their fascinating physical behaviors and possible novel applications. In this review, we highlight the progress in single-phase ME multiferroic oxides research in terms of the classification depending on the physical origins of ferroic properties and the corresponding examples for each case, i.e., material by material, along with their ME multiferroic properties including saturation magnetization, spontaneous polarization, (anti)ferromagnetic/ferroelectric transition temperature, and ME coefficient. The magnetoelectrically-active applications of high expectancy are presented by citing the representative examples such as magnetoelectric random-access-memory and multiferroic photovoltaics. Furthermore, we discuss how the development of ME multiferroic oxides should proceed by considering the current research status in terms of developed materials and designed applications. We believe that this short review will provide a basic introduction for the researchers new to this field.

Multiferroic and energy-storage characteristics of polycrystalline Ca-doped BiFeO3 thin films on Si substrates

안윤호,손종역 한국세라믹학회 2023 한국세라믹학회지 Vol.60 No.2

Significant progress has been made in the enhancement of multiferroic properties with possibilities for energy harvesting and storage applications. In this study, BiFeO3 (BFO) thin films were doped with Ca, and the multiferroic, piezoelectric, and energy-storage properties of Bi1−xCaxFeO3−δ (x = 0.3, BCFO) thin films were compared with those of BFO to investigate the effects of the doping. The BCFO thin films were deposited on Pt/TiO2/SiO2/Si substrates using pulsed laser deposition. The BCFO thin films having a polycrystalline structure, exhibited improved crystallinity and larger grains, compared with the BFO thin films. The high crystallinity further resulted in the BCFO thin films exhibiting improved leakage current, ferroelectric, and ferromagnetic characteristics, compared with the BFO thin films. The morphotropic phase boundary formed in the mixed crystal phase, which was driven by the Ca doping, and it improved the piezoelectric coefficients of the BCFO thin films. Additionally, we found that the BCFO thin films have superior energy-storage characteristics, compared with the BFO thin films, owing to the improved ferroelectric properties. Our findings suggest that the Ca doping of the BFO thin films improves their multiferroic properties, piezoelectric response, and energy-storage characteristics.

Multiferroic CoFe2O4-Pb(Zr,Ti)O3 Nanostructures

Pham Duc Thang,Mai T. N. Pham,G. Rijnders,D. H. A. Blank,Nguyen Huu Duc,J. C. P. Klaasse,E. Bruck 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.5

Multiferroic CoFe₂O₄-Pb(Zr,Ti)O₃ films were prepared on TiO₂-terminated (001) Nb-doped SrTiO3 substrates by using pulsed laser deposition (PLD). The lms were epitaxial and exhibited a large in-plane magnetic anisotropy and good ferroelectric properties. A decrease in the magneti- zation around the ferroelectric Curie temperature indicated magnetoelectric coupling between the magnetostrictive and the piezoelectric phases, which allows interconversion of energy stored in the electric and the magnetic elds and provides great potential for applications as next-generation multi-functional devices. Multiferroic CoFe₂O₄-Pb(Zr,Ti)O₃ films were prepared on TiO₂-terminated (001) Nb-doped SrTiO3 substrates by using pulsed laser deposition (PLD). The lms were epitaxial and exhibited a large in-plane magnetic anisotropy and good ferroelectric properties. A decrease in the magneti- zation around the ferroelectric Curie temperature indicated magnetoelectric coupling between the magnetostrictive and the piezoelectric phases, which allows interconversion of energy stored in the electric and the magnetic elds and provides great potential for applications as next-generation multi-functional devices.

Effect of Ba and Ho co-doping on crystal structure, phase transformation, magnetic properties and dielectric properties of BiFeO3

Jogender Singh, Ashish Agarwal,Ashish Agarwal,Sujata Sanghi,Tanvi Bhasin,Manisha Yadav,Umesh Bhakar,Ompal Singh 한국물리학회 2019 Current Applied Physics Vol.19 No.3

Multiferroics having composition Bi0.80-xBa0.20HoxFeO3 (BBFO, BBHFO5, BBHFO10, BBHFO15 and BBHFO20 for x=0.0, 0.05, 0.10, 0.15 and 0.20 respectively) were synthesized by method of solid state reaction. The crystal structure has been studied using X-ray diffraction technique. The X-ray patterns show enormous transform in crystal structure at concentration x=0.20. The Rietveld refinement of XRD patterns indicates that at concentration x=0.0 sample have rhombohedral structure with R3c space group while for the concentration x=0.05, 0.10, 0.15 and 0.20, the mixed phase including rhombohedral R3c and triclinic P1 space groups were obtained with best fitting. This phase transformation in crystal structure is observed due to mismatching of ionic radii of doped ions and parent ions. Magnetic properties of all samples were carried out by using vibrating sample magnetometry. M-H hysteresis loops shows that with doping of Ba and Ho antiferromagnetic BiFeO3 (BFO) transforms into ferromagnetic. The dielectric and ferroelectric measurements were carried out which shows that dielectric constant, dielectric loss and ferroelectric properties are enhanced with co-doping of Ho in comparison of the pristine BFO due to structure deformation and decrease in oxygen vacancies with higher concentration of Ho. Significant improvement has been observed in dielectric constant and remnant magnetization values with increasing content of Ho and decrease in the dielectric loss.