The first book on this topic provides a comprehensive and well-structured overview of the fundamentals, synthesis and emerging applications of magnetoelectric polymer materials.
Following an introduction to the basic aspects of polymer based magnetoelectric materials and recent developments, subsequent chapters discuss the various types as well as their synthesis and characterization. There then follows a review of the latest applications, such as memories, sensors and actuators. The book concludes with a look at future technological advances.
An essential reference for entrants to the field as well as for experienced researchers.
S. Lanceros-Méndez graduated in physics at the University of the Basque Country, Leioa, Spain. He obtained his PhD degree at the Institute of Physics of the Julius-Maximilians-Universität Würzburg, Germany. He was Research Scholar at Montana State University, Bozeman, MT, USA and visiting scientist at the, Pennsylvania State University, USA and University of Potsdam, among others. Since 2016 he is Ikerbasque Professor at the BCMaterials, Basque Center for Materials, Applications and Nanostructures, Derio, Spain. He is Associate Professor at the Physics Department of the University of Minho, Portugal (on leave), where he belongs to the Center of Physics. From 2012 to 2014 he was also Associate Researcher at the INL - International Iberian Nanotechnology Laboratory. His work is focused in the area of smart materials for sensors and actuators, energy and biomedical applications.
Pedro Martins graduated in Physics and Chemistry in 2006 and received the PhD degree in Physics in 2012, both from the University of Minho, Braga, Portugal. From 2012 to 2014 he was also Visiting Researcher at the INL - International Iberian Nanotechnology Laboratory. He is now a postdoctoral researcher in the University of Minho, Braga, Portugal and his work is focused on polymer-based magnetoelectric materials and electroactive polymers for advanced technological applications. He collaborates with the Basque Country University, Spain; Wollongong University, Australia and Cambridge University, United Kingdom, among others.
Magnetoelectric Effect of Functional Materials: Theoretical Analysis, Modeling, and Experiment
Jia-Wei Zhang1, 2, Hong-Yan Guo1, Xiao Chen1 and Rui-Tong Liu3
1Northeast Electric Power University, School of Electrical Engineering, 169 Changchun Road, Jilin, 132013, China
2Harbin University of Science and Technology, Key Laboratory of Engineering Dielectric and its Application of Ministry of Education, Harbin, China
3State Grid Liaoning Province Power Company Limited Power Research Institute, Shenyang 110181, China
1.1 Introduction of Magnetoelectric Effect
Magnetoelectric (ME) effect is defined as an induced dielectric polarization under an applied magnetic field and/or an induced magnetization under an external electric field . Materials with ME properties are called magnetoelectric materials (MMs). There are single- and multiphase MMs. Single-phase MMs contain only one type of structure. Little research has been done on single-phase MMs because the intrinsic ME coupling in single-phase compounds is generally quite weak, especially at room temperature. The ME effect in multiphase composite materials is the product of ferromagnetic magnetostriction and ferroelectric piezoelectricity .
1.1.1 Single-Phase Magnetoelectric Materials
Single-phase materials possessing both antiferromagnetic and ferroelectric constituents in the same phase are the first discovered ME materials. In 1894, Pierre Curie predicted the possibility of an intrinsic ME effect in some single-phase materials. Although the terminology "magnetoelectric effect" was defined by Debye in 1926, it remained a speculation until 1960 when the first real MM Cr2O3 was discovered . In 1969, Homreich discovered some candidates of MMs based on the magnetic point group, including Fe2TeO6, Cr2TeO6, FeCrWO6, Cr2WO6, Ca2FeAlO5, and FeNaO2. In 1970, BiFeO3 was found to be unique among various ME multiferroics because of its exceptionally high antiferromagnetic and ferroelectric transition temperatures well above room temperature . An important breakthrough in 2003 was the discovery of large room-temperature ferroelectric polarization in coexistence with magnetization in BiFeO3 thin films, which presents a theoretical investigation on BiFeO3 bulks, films, and heterostructures.
1.1.2 Multiphase Materials
In the past century, to overcome the drawbacks of weak ME effect in single-phase materials, ME materials have evolved from single-phase compounds to multiphase materials. Multiphase materials are usually prepared by combining ferromagnetic and ferroelectric phases in the bulk and laminated forms.
In 1948, Tellegen failed to synthesize bulk composites with extrinsic ME effect by combining two different types of macroscopic particle composites with magnetic and electric dipole moments as the beginning of the investigation. In the early 1990s, bulk composites of ferrites and BaTiO3 or Pb(Zr, Ti)O3 (PZT) had been prepared by Newnham's group and Russian scientists through a conventional sintering process. In 2001, Patankar et al. performed extended experiments on several doped ferrite/titanate bulk composites such as CuFe1.8Cr0.2O4/Ba0.8Pb0.2TiO3. Recently, experiments on many doped titanate/ferrite composites were reported. The piezoelectric constituents include Bi4Ti3O12, polyvinylidene fluoride (PVDF), PbMg1/3V2/3O3, and PbX1/3Nb2/3O3-PbTiO3 (X = Mg, Zn), and the alternative magnetostrictive constituents include LiFe5O8, yttrium iron garnet (YIG), and Permendur .
Laminated composites are typically made of magnetostrictive material layers bonded with piezoelectric material layers with different arrangements of the magnetization and polarization directions. Figure 1.1 shows an example of the epoxy-bonded-type three-phase laminated composites constructed by sandwiching a thickness-polarized PZT plate between two length-magnetized epoxy-bonded Terfenol-D particulate composite plates .
Figure 1.1 Schematic of proposed laminated composites configuration of magnetostrictive and piezoelectric materials .
Recently, the direct-coupling Lorentz force effect in the metallic phase with the piezoelectric effect in the piezoelectric phase induced by an extrinsic "dc" ME effect was observed in metallic/piezoelectric heterostructures. Guiffard et al. developed an ME current sensor with ME coupling in a simple piezoelectric unimorph bender induced by the eddy currents within the silver electrodes of the piezoelectric ceramic PZT subjected to ac magnetic flux . Therefore, the MMs without the magnetic phase can be used in ME current sensors.
1.2 Applications of Magnetoelectric Effect
So far bulk composites, laminated composites, and metallic/piezoelectric heterostructures exhibit practically useful ME effect above room temperature. Nowadays, there are some main promising device applications, including ME sensors, ME transducers, ME microwave devices, and so on.
1.2.1 Magnetoelectric Sensors
In the work of Leung et al., a high-sensitive magnetoelectric sensor was obtained using ME composites by increasing the corresponding ME voltage coefficient of 27 mV Oe-1 during measurement .
The working principle of the sensor was as follows: when an ac vortex magnetic field was induced along the length of the electric cable by an ac electric current in the cable in accordance with Ampère's law, the sensor transduced the ac vortex magnetic field to an ac electric voltage based on the giant ME effect.
1.2.2 Magnetoelectric Transducer
Today, the magnetoelectric transducer has become a hot research topic, partly because the energy harvest from the environment has been considered to be a significant investigation by researchers. There are four main types of vibration energy harvesters (VEHs), namely electrostatic, piezoelectric, ME, and electromagnetic (EM) .
The VEH that consisted of a ME/EM composite transducer, a cantilever beam, and magnetic circuits was reported by Qiu and coworkers. The schematic diagram of the proposed ME/EM composite VEH is shown in Figure 1.2a. The ME/EM composite transducer was placed at the tip of the cantilever beam and could act as masses, which lowered the natural frequency of the cantilever beam and scavenged lower frequency vibration energy from environments more effectively. The schematic diagram of the ME/EM composite transducer is shown in Figure 1.2b. The transducer was made up of a coil and a three-phase laminate, which is composed of two Terfenol-D layers and a piezoelectric layer.
Figure 1.2 Schematic diagrams of (a) the proposed ME/EM composite VEH and (b) the ME/EM composite transducer .
The working principle of the ME/EM composite transducer is as follows: based on Faraday's law of electromagnet induction, when the composite transducers undergo alterations of magnetic flux gradient generated by a vibration source, the coil would induce an electromotive force due to the relative motion between the coil and the magnetic circuit. Meanwhile, based on the ME effect, the stresses induced by Terfenol-D layers would transmit to the piezoelectric layer, and finally the electrical power is generated.
1.2.3 Magnetoelectric Microwave Devices
Magnetoelectric microwave devices are the devices that can be tuned by magnetostatic field and electrostatic field when the devices are applied with composited MMs. Because of the advantages of low power consumption, low noise, and high-quality factor, the ME microwave devices have great potential in mobile communication system, electronic warfare systems, active phased-array radar under the national defense platform, and so on .
The attenuator with a microstrip transmission line on dielectric substrate and ME resonator was reported by Tatarenko et al. With the influence of an external electrical field, the ME effect shifted the line of FMR (ferromagnetic resonance), which is a powerful tool for the studies of microwave ME interaction in ferrite-piezoelectric structures .
As shown in Figure 1.3, the sample of layered structure consisted of the magnetic part with the YIG thin film placed on the GGG film and the piezoelectric part with the thin PMN-PT plate. Based on resonance ME effect phenomena, when applying the control voltage to electrodes of the ME resonator, a shift of FMR line would occur due to the resonance ME effect, and hence electrical tuning is realized.
Figure 1.3 Design of microstrip ME attenuator and ME resonator .
Tatarenko and Bichurin 2012 https://www.hindawi.com/journals/acmp/2012/286562/abs/. Used under CC BY 3.0 license.
1.3 Magnetoelectric Effect of Piezoelectric Ceramic
Previous reports of magnetoelectric materials with magnetostrictive/piezoelectric magnetoelectric laminates have been discussed by many researchers. However, it requires ac current supply on the electrically conductive Terfenol-D strips. Recently, the ME effect in the piezoelectric beam based on torque moment, which is generated from Lorentz force on the electrodes without magnetic phase in the sample and also without applying power source on the piezoelectric beam, has been reported by Zhang et al.
As shown in Figure 1.4, the measuring system was composed of a PZT beam and an electric wire, which induced the ac magnetic field that penetrated into the surface of the PZT beam. When the metal electrodes of the PZT beam were subjected...