Ferroelectrics go bananas

Scott, J. F.

doi:10.1088/0953-8984/20/02/021001

Cited by 540 publications

(409 citation statements)

References 24 publications

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“…1g) As for the FE2 phase, since the pyroelectric current emerges above T Cr and forms a broad peak at about 125 K, its origin is clearly not related to any spin ordering. Such a feature, on the one hand, may be ascribed to an extrinsic effect such as space charges trapped at the grain boundaries or possible defects as reported elsewhere [46,47]. On the other hand, we noticed that some ABO 3 perovskites like YCrO 3 and SmCrO 3 with Cr 3+ 12 ions at the B site also displayed similar electric polarizations above the AFM temperatures [48,49].…”

supporting

confidence: 83%

Observation of Magnetoelectric Multiferroicity in a Cubic Perovskite System:LaMn3Cr4O12

et al. 2015

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The magnetoelectric multiferroicity is not expected to occur in a cubic perovskite system due to the high structural symmetry. By versatile measurements in magnetization, dielectric constant, electric polarization, neutron and X-ray diffraction, Raman scattering as well as theoretical calculations, we reveal that the A-site ordered perovskite LaMn 3 Cr 4 O 12 with cubic symmetry is a novel spin-driven multiferroic system with strong magnetoelectric coupling effects. When magnetic field is applied in parallel/perpendicular to electric field, the ferroelectric polarization can be enhanced/suppressed significantly. The unique multiferroic phenomenon observed in this cubic perovskite cannot be understood by conventional spin-driven microscopic mechanisms. Instead, a nontrivial effect involving the interactions between two magnetic sublattices is likely to play a crucial role. 3The magnetoelectric (ME) multiferroicity with coupled ferroelectric and magnetic orders have received much attention due to their great potential for numerous applications [1][2][3][4][5][6][7][8]. Perovskite is one of the most important material systems for multiferroic study. Since the discovery of multiferroic behaviors in perovskite BiFeO 3 and TbMnO 3 [2,3], a large number of multiferroic materials with different physical mechanisms have been found in the last decade [9][10][11][12][13]. Among them, the spin-induced multiferroics have received the most attention because the ferroelectricity is induced by magnetic structures so that a strong ME coupling would be expected [14][15][16]. Several theories such as spin-current model (or inverse Dzyaloshinskii-Moriya interaction), exchange striction mechanism and d-p hybridization mechanism have been proposed to account for the spin-induced ferroelectricity in ME multiferroics by special spin textures such as non-collinear spiral spin structures and collinear E-type antiferromagnetic (AFM) structure with zigzag spin chains [17][18][19][20][21]. It is well known that a cubic perovskite lattice is unfavorable for ferroelectricity due to the existence of an inversion center. However, the total symmetry for an ME multiferroics is the product of the crystal and magnetic symmetries. Therefore, in principle, it is possible to find an ME multiferroics in a cubic perovskite system if its magnetic structure breaks the space inversion symmetry. Nevertheless, such an intriguing case has never been found in previous studies. 4The A-site ordered perovskite with a chemical formula of AA′ 3 B 4 O 12 provides an opportunity for searching ME multiferroics in a cubic lattice.This type of ordered perovskite can be formed when three quarters of the A-site of a simple ABO 3 perovskite is substituted by a transition-metal ion A′ (Fig. 1a) [22]. Since both A′ and B sites accommodate magnetic transition-metal ions, multiple magnetic interactions may develop while the crystal structure can be finely tuned by selecting appropriate A′ and B elements to maintain a cubic lattice [23][24][25][26][27]. In this lette...

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confidence: 83%

Observation of Magnetoelectric Multiferroicity in a Cubic Perovskite System:LaMn3Cr4O12

et al. 2015

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“…Nevertheless such loops are nothing but artefacts resulting from the relative high conductivity of LuFe 2 O 4 at these temperatures. 20 Indeed, the apparent ferroelectric remanent polarization values for LuFe 2 O 4 at about 120 K coming out from the mentioned works, that is, 0.25 (Ref. 18 and 0.05 (Ref.…”

Section: Introductionmentioning

confidence: 93%

“…As the temperature increases, an apparent hysteresis cycle appears like those reported earlier 18,19 which actually reflects the increase of the sample conductivity. 20 The same behavior was repeated for the polycrystalline sample. Additionally, polarization measurements were carried out down to 10 K. Figure 3(b) shows the polarization curve for the highest electric field permitted by the experimental setup (of about 30 kV/cm) at 10 K for the single crystal.…”

Section: B Electrical Polarizationmentioning

confidence: 99%

Intrinsic electrical properties of LuFe2O4

et al. 2013

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We here revisit the electrical properties of LuFe 2 O 4 , compound candidate for exhibiting multiferroicity. Measurements of dc electrical resistivity as a function of temperature, electric-field polarization measurements at low temperatures with and without magnetic field, and complex impedance as a function of both frequency and temperature were carried out in a LuFe 2 O 4 single crystal, perpendicular and parallel to the hexagonal c axis, and in several ceramic polycrystalline samples. Resistivity measurements reveal that this material is a highly anisotropic semiconductor, being about two orders of magnitude more resistive along the c axis. The temperature dependence of the resistivity indicates a change in the conduction mechanism at T CO ≈ 320 K from thermal activation above T CO to variable range hopping below T CO . The resistivity values at room temperature are relatively small and are below 5000 cm for all samples but we carried out polarization measurements at sufficiently low temperatures, showing that electric-field polarization curves are a straight line as expected for a paraelectric or antiferroelectric material. Furthermore, no differences are found in the polarization curves when a magnetic field is applied either parallel or perpendicular to the electric field. The analysis of the complex impedance data corroborates that the claimed colossal dielectric constant is a spurious effect mainly derived from the capacitance of the electrical contacts. Therefore, our data unequivocally evidence that LuFe 2 O 4 is not ferroelectric.

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“…It has been previously discussed that materials that show saturation in polarization and have concave region in P−E plot are true ferroelectric. 20 Co inside BTO shows a saturation polarization and concave P(E) curve, thereby indicating the presence of intrinsic ferroelectricity in this sample. This sample also showed a very small leakage current (Figure 3b) compared to other morphologies ( Figure S9), an important consideration for device design, so we focused our investigations on this morphology.…”

mentioning

confidence: 84%

Hybrid Multiferroic Nanostructure with Magnetic–Dielectric Coupling

et al. 2012

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The development of methods to economically synthesize single wire structured multiferroic systems with room temperature spin−charge coupling is expected to be important for building next-generation multifunctional devices with ultralow power consumption. We demonstrate the fabrication of a single nanowire multiferroic system, a new geometry, exhibiting room temperature magnetodielectric coupling. A coaxial nanotube/nanowire heterostructure of barium titanate (BaTiO 3 , BTO) and cobalt (Co) has been synthesized using a template-assisted method. Room temperature ferromagnetism and ferroelectricity were exhibited by this coaxial system, indicating the coexistence of more than one ferroic interaction in this composite system. KEYWORDS: Multiferroic materials, 1D heterostructure, barium titanate nanotubes, Co nanowires, spin−charge coupling, magnetocapacitance O ne-dimensional (1D) nanostructures such as nanotubes and nanowires attract considerable scientific attention because of their novel structure and physical properties, which can differ significantly from their bulk or thin film counter analogues. 1−3 From a practical standpoint, nanowires and nanotubes are the focus of intensive research effort owing to their unique applications in the fabrication of nanoscale devices and interconnects. 4 Multiferroic materials exhibit more than one ferroic order simultaneously, such as ferromagnetic/antiferromagnetic or ferroelectric/ferroelastic/ferrotoroidic. 5 However, the abundance of intrinsic multiferroic materials is sharply limited by the competing symmetry requirements for each type of ferroic order. Generally, ferroelectricity is associated with an empty outer shell d electrons (known as d 0 ness) while magnetic ordering requires unpaired d or f electrons, i.e., partially filled. 6 While these types of fundamental incompatibilities can make it challenging to identify intrinsic multiferroics, forming nanoscale composites of different ferroic materials to produce multiferroic superstructures provides an alternate method to introduce the desired materials properties. The coupling between the ferroic order parameters can be modulated by heteroepitaxial strain and crystal chemistry. 6,7 The development of magnetoelectric multiferroics, having coexisting magnetic and ferroelectric order, opens the possibility of controlling the magnetic/electric structure using either electric or magnetic fields. This type of cross-control requires a significant coupling between charge and spin or, in other words, a coupling between electric polarization and magnetic moment. This characteristic behavior is of considerable scientific and technological interest, and a number of studies are being conducted to design new multiferroic structures to foster a great understanding of the factors that promote the coupling between magnetic and ferroelectric order parameters. 6−18 Potential applications for multiferroic materials range from multiple-state data storage elements, to magnetically tunable high frequency electrical devices such ...

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Ferroelectrics go bananas

Cited by 540 publications

References 24 publications

Observation of Magnetoelectric Multiferroicity in a Cubic Perovskite System:LaMn3Cr4O12

Observation of Magnetoelectric Multiferroicity in a Cubic Perovskite System:LaMn3Cr4O12

Intrinsic electrical properties of LuFe2O4

Hybrid Multiferroic Nanostructure with Magnetic–Dielectric Coupling

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