Multiferroic magnetoelectric materials, which simultaneously exhibit ferroelectricity and ferromagnetism, have recently stimulated a sharply increasing number of research activities for their scientific interest and significant technological promise in the novel multifunctional devices. Natural multiferroic single-phase compounds are rare, and their magnetoelectric responses are either relatively weak or occurs at temperatures too low for practical applications. In contrast, multiferroic composites, which incorporate both ferroelectric and ferri-/ferromagnetic phases, typically yield giant magnetoelectric coupling response above room temperature, which makes them ready for technological applications. This review of mostly recent activities begins with a brief summary of the historical perspective of the multiferroic magnetoelectric composites since its appearance in 1972. In such composites the magnetoelectric effect is generated as a product property of a magnetostrictive and a piezoelectric substance. A...

Multiferroic magnetoelectric composites: Historical perspective, status, and future directions

We review the recent developments in the electric field control of magnetism in multiferroic heterostructures, which consist of heterogeneous materials systems where a magnetoelectric coupling is engineered between magnetic and ferroelectric components. The magnetoelectric coupling in these composite systems is interfacial in origin, and can arise from elastic strain, charge, and exchange bias interactions, with different characteristic responses and functionalities. Moreover, charge transport phenomena in multiferroic heterostructures, where both magnetic and ferroelectric order parameters are used to control charge transport, suggest new possibilities to control the conduction paths of the electron spin, with potential for device applications.

https://iopscience.iop.org/article/10.1088/0953-8984/24/33/333201/pdf

Electric field control of magnetism in multiferroic heterostructures

Materials science is recognized as one of the main factors driving development and economic growth. Since the silicon industrial revolution of the 1950s, research and developments in materials and solid state science have radically impacted and transformed our society by enabling the emergence of the computer technologies, wireless communications, Internet, digital data storage, and widespread consumer electronics. Today's emergent topics in solid state physics, such as nano-materials, graphene and carbon nano-tubes, smart and advanced functional materials, spintronic materials, bio-materials, and multiferroic materials, promise to deliver a new wave of technological advances and economic impact, comparable to the silicon industrial revolution of the 1950s.The surge of interest in multiferroic materials over the past 15 years has been driven by their fascinating physical properties and huge potential for technological applications. This article addresses some of the fundamental aspects of solid-state mult...

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Fundamentals of Multiferroic Materials and Their Possible Applications

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Recently, the magnetoelectric (ME) effect—dielectric polarization of a material under magnetic field, or induced magnetization under an electric field—has become the focus of significant research interests. The primary requirement for the observance of said effect is the coexistence of magnetic and electric dipoles. Most of the known single phase materials suffer from the drawback that the ME effect is quite small, even at low temperatures limiting their applicability in practical devices. Better alternatives are ME composites, which have large magnitudes of the ME voltage coefficient. Composites exploit the product property of materials; where the ME effect is realized by combining magnetostrictive and piezoelectric phases that independently are not ME, but acting together (i.e., their product) result in a ME effect. In this review article, we survey recently reported results concerning ME composites, focusing on ME particulate (synthesized via a controlled precipitation technique) and laminated composites. The article also provides a survey of the compositions and magnitudes of the ME coefficients reported in the literature; a brief description of the analytical models developed to explain and predict the behavior of composites; and discuss several applications that are made possible by enhanced ME effects.

Recent advancements in magnetoelectric particulate and laminate composites

We present the first data and theory for the bias magnetic field dependence of magnetoelectric coupling in the electromechanical resonance (EMR) region for ferromagnetic-piezoelectric heterostructures. Trilayers of Permendur, a $\mathrm{Co}\ensuremath{-}\mathrm{Fe}\ensuremath{-}\mathrm{V}$ alloy, and lead zirconate titanate were studied. Measurements of the magnetoelectric (ME) voltage coefficient ${\ensuremath{\alpha}}_{E}$ indicate a strong ME coupling in the low-frequency range and a giant ME effect due to EMR at $200--300\phantom{\rule{0.3em}{0ex}}\mathrm{kHz}$ for radial modes and at $\ensuremath{\sim}2.7\phantom{\rule{0.3em}{0ex}}\mathrm{MHz}$ for thickness modes. Data were obtained for the bias field $H$ dependence of two key parameters, the EMR frequency ${f}_{r}$ and the ME coefficient ${\ensuremath{\alpha}}_{E,R}$ at resonance. With increasing $H$, an increase in ${f}_{r}$ and a rapid rise and fall in ${\ensuremath{\alpha}}_{E,R}$ are measured. In our model we consider two mechanisms for the magnetic field influence on ME interactions: (i) a shift in the EMR frequency due to changes in compliance coefficients ($\ensuremath{\Delta}E$ effect) and (ii) variation in the piezomagnetic coefficient that manifests as a change in ${\ensuremath{\alpha}}_{E,R}$. Theoretical profiles of ${\ensuremath{\alpha}}_{E}$ vs frequency and estimates of frequency shift based on the $\ensuremath{\Delta}E$ effect are in excellent agreement with the data.

Resonant magnetoelectric coupling in trilayers of ferromagnetic alloys and piezoelectric lead zirconate titanate: The influence of bias magnetic field

The strength of magnetoelectric (ME) coupling at 10Hz–3MHz has been measured in trilayers of Fe, Co, or Ni and lead zirconate titanate (PZT). The strongest ME coupling is measured for trilayers with Ni and the weakest in Co. Data on ME voltage coefficient αE versus bias magnetic field H for Fe–PZT–Fe show unique features including zero crossing and sign reversal. Measurements of frequency dependence of αE reveal a giant ME coupling due to the electromechanical resonance at 200–300kHz for radial modes and at ∼2.7MHz for thickness modes. Theoretical estimates of field and frequency dependence of αE are in very good agreement with the data.

Frequency and field dependence of magnetoelectric interactions in layered ferromagnetic transition metal-piezoelectric lead zirconate titanate

The nature of low-frequency magnetoelectric (ME) coupling has been investigated in bilayers of single crystal lead magnesium niobate-lead titanate (PMN-PT) and yttrium iron garnet (YIG). Samples with (001) PMN-PT and polycrystalline, single crystal, or epitaxial thin films of YIG were studied. The ME coupling is the weakest in bilayers with polycrystalline YIG. A dramatic strengthening of ME interactions occurs in samples with single crystal (111) YIG. The strongest ME coupling occurs in bilayers with (110) epitaxial YIG film. The voltage coefficients show significant variation with the orientation of the bias magnetic field H; it is maximum for H‖⟨1i¯1⟩ and is minimum for H‖⟨001⟩. The transverse coefficient increases linearly with increasing thickness of YIG film. Data analysis reveals that strong magnetomechanical coupling in thin film YIG is the cause of enhancement in the ME coupling.

Magnetoelectric interactions in bilayers of yttrium iron garnet and lead magnesium niobate-lead titanate: Evidence for strong coupling in single crystals and epitaxial films

The magnetoelectric (ME) gyrator is a device that can convert not only active and reactive impedances, but also current and voltage. In this work, we have carried out research on three gyrators structures based on Terfenol-D/PZT/Terfenol-D, Metglas/PZT/Metglas and Nickel/PZT/Nickel. Detailed investigations of the ME gyrator based on these trilayer composite structures have been performed at the electromechanical resonance frequency.

C. P. De Vreugd

Papers

Resonant magnetoelectric coupling in trilayers of ferromagnetic alloys and piezoelectric lead zirconate titanate: The influence of bias magnetic field

Frequency and field dependence of magnetoelectric interactions in layered ferromagnetic transition metal-piezoelectric lead zirconate titanate

Magnetoelectric interactions in bilayers of yttrium iron garnet and lead magnesium niobate-lead titanate: Evidence for strong coupling in single crystals and epitaxial films

Magnetoelectric gyrator