How the Giant Magnetoelectric Effect Occurs in Bismuth Ferrite
May 23, 2016 | MIPTEstimated reading time: 3 minutes
A team of scientists from the Moscow Institute of Physics and Technology (MIPT), the National Research University of Electronic Technology (MIET), and the Prokhorov General Physics Institute have proposed a theoretical model that explains the unexpectedly high values of the linear magnetoelectric effect in BiFeO3 (bismuth ferrite) that have been observed in a number of experiments. The team also suggested a way of further enhancing the effect. The results of the study have been published in the journal Physical Review B.
One particular feature of bismuth ferrite is that in bulk samples, spins of Fe3+ iron ions are arranged in the form of a cycloid. This spin structure can be destroyed by a strong magnetic field or mechanical stress. Without a spin cycloid, bismuth ferrite exhibits a large linear magnetoelectric effect, and this effect was the focal point of the study.
Multiferroics and the magnetoelectric effect
Multiferroics are materials that simultaneously exhibit different ferroic orders, including magnetic, ferroelectric and/or ferroelastic. If there is an interaction between electric and magnetic subsystems in a material, a magnetoelectric (ME) effect may occur.
The magnetoelectric effect is when electric polarization occurs under the influence of an external magnetic field and magnetization occurs under the influence of an electric field. This allows an electric field to be used to control the magnetic properties of a material and a magnetic field to be used to control the electric properties. If the value of the ME effect is high (dozens or hundreds of times higher than normal), it is called a giant ME effect.
The main use of the magnetoelectric effect is in variable and static magnetic field sensors. These sensors are used in navigation systems, electric motors, and also in vehicle ignition systems. Compared to similar devices based on the Hall effect or magnetoresistance, sensors based on the ME effect are more sensitive (according to research, up to one million times more sensitive) and they are also relatively cheap to manufacture.
The ME effect offers exciting possibilities for the use of multiferroics in new types of magnetic memory, e.g. ROM – read only memory. The ME effect could also potentially be used to create high-precision equipment for working with radiation in the microwave range, and to wirelessly transmit power to miniaturized electronic devices.
Bismuth ferrite
The subject of the study was bismuth ferrite (BiFeO3) – a highly promising multiferroic that is very promising in terms of its practical applications. It is planned to be used to create ultra energy-efficient magnetoelectric memory.
In addition, bismuth ferrite exhibits a magnetoelectric effect at room temperature, while in most other magnetoelectrics an ME effect of this magnitude is only observed at extremely low temperatures (below -160 degrees Celsius). Bismuth ferrite is an antiferromagnetic, which means that the magnetic moments of its magnetic sublattices (structures formed by atoms with the same parallel spins) cancel each other out, and the total magnetization of the material is close to zero. However, the spatial arrangement of the spins forms the same cycloidal spin structure (Fig. 1).
In the 1980s it was thought that this multiferroic exhibited only a quadratic magnetoelectric effect (i.e. polarization is quadratically proportional to the applied magnetic field). The fact that the linear magnetoelectric effect “went unnoticed” for a long time had to do with the spin cycloid (Fig. 1): due to the spin cycloid structure, certain characteristics, such as magnetization and the magnetoelectric effect “average out” to zero. However, when bismuth ferrite is placed in a strong magnetic field (greater than a certain critical value), the structure is destroyed and this is accompanied by the emergence of a linear ME effect (when polarization is linearly proportional to the applied field).
Early experiments indicated a low value of the linear magnetoelectric effect in bismuth ferrite (almost one thousand times lower than the actual value), however later experimental studies revealed a large ME effect and it was also demonstrated that by using it in layered structures, record values of the magnetoelectric effect can be achieved.
Suggested Items
Vertical Aerospace Adopts Universal Fast-Charging Standard to Accelerate eVTOL Deployment
04/01/2025 | BUSINESS WIREVertical Aerospace (Vertical), a global aerospace and technology company that is pioneering electric aviation, announces it will adopt the Combined Charging Standard (CCS) for the VX4, joining BETA Technologies and Archer Aviation in driving a universal, fast-charging system for electric vertical take-off and landing (eVTOL) aircraft.
Mazda, ROHM Begin Joint Development of Automotive Components Using Next-Generation Semiconductors
03/28/2025 | ROHMMazda Motor Corporation and ROHM Co., Ltd. have commenced joint development of automotive components using gallium nitride (GaN) power semiconductors, which are expected to be the next-generation semiconductors.
Life in the Fast Lane: A Smooth Ride for Bill Cardoso's New Business Converting Cobra Roadsters to Electric
03/26/2025 | Barry Matties, IPC CommunityBill Cardoso has established quite a list of accomplishments behind his name, from nuclear scientist, organic farmer, and IPC member to entrepreneur and owner of the largest U.S.-based manufacturer in the field of X-ray inspection. Three years ago, though, he brought home a Cobra roadster, and his son’s visceral reaction led to yet another new business venture.
Aismalibar to Showcase Advanced Thermal Management Solutions at APEC 2025
03/13/2025 | AismalibarAismalibar, a global leader in high-performance thermal management materials, is set to exhibit at APEC 2025 (Applied Power Electronics Conference) in Atlanta, Georgia, from March 16–20, 2025. As the premier event for power electronics professionals, APEC provides a crucial platform for industry leaders to explore the latest advancements in thermal interface materials (TIMs), high-performance PCB laminates, and insulated metal substrates (IMS).
Hannah Nelson: The Inspiring Journey of an Emerging Engineer
03/11/2025 | I-Connect007 Editorial TeamAt last year’s IPC APEX EXPO, former IPC Emerging Engineer Hannah Nelson had the opportunity to reflect on her inspiring journey into the world of engineering, from her education at Valparaiso University to her internship and her first job at Texas Instruments. From pivotal moments and the unexpected turns that helped shape her early career and passion for electrical engineering, her story highlights the importance of interdisciplinary collaboration, taking opportunities that arise early on, finding confidence in one's voice, and the rewards of pursuing one's passions within the engineering field.
Copyright © 2025 I-Connect007 | IPC Publishing Group Inc. All rights reserved.
Log in