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Nicola A. Spaldin

Bio: Nicola A. Spaldin is an academic researcher from ETH Zurich. The author has contributed to research in topics: Ferroelectricity & Multiferroics. The author has an hindex of 76, co-authored 280 publications receiving 34872 citations. Previous affiliations of Nicola A. Spaldin include University of California & University of California, Santa Barbara.


Papers
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Journal ArticleDOI
14 Mar 2003-Science
TL;DR: Enhanced polarization and related properties in heteroepitaxially constrained thin films of the ferroelectromagnet, BiFeO3, and combined functional responses in thin film form present an opportunity to create and implement thin film devices that actively couple the magnetic and ferroelectric order parameters.
Abstract: Enhancement of polarization and related properties in heteroepitaxially constrained thin films of the ferroelectromagnet, BiFeO3, is reported. Structure analysis indicates that the crystal structure of film is monoclinic in contrast to bulk, which is rhombohedral. The films display a room-temperature spontaneous polarization (50 to 60 microcoulombs per square centimeter) almost an order of magnitude higher than that of the bulk (6.1 microcoulombs per square centimeter). The observed enhancement is corroborated by first-principles calculations and found to originate from a high sensitivity of the polarization to small changes in lattice parameters. The films also exhibit enhanced thickness-dependent magnetism compared with the bulk. These enhanced and combined functional responses in thin film form present an opportunity to create and implement thin film devices that actively couple the magnetic and ferroelectric order parameters.

5,387 citations

Journal ArticleDOI
TL;DR: Novel device paradigms based on magnetoelectric coupling are discussed, the key scientific challenges in the field are outlined, and high-quality thin-film multiferroics are reviewed.
Abstract: Multiferroic materials, which show simultaneous ferroelectric and magnetic ordering, exhibit unusual physical properties — and in turn promise new device applications — as a result of the coupling between their dual order parameters. We review recent progress in the growth, characterization and understanding of thin-film multiferroics. The availability of high-quality thin-film multiferroics makes it easier to tailor their properties through epitaxial strain, atomic-level engineering of chemistry and interfacial coupling, and is a prerequisite for their incorporation into practical devices. We discuss novel device paradigms based on magnetoelectric coupling, and outline the key scientific challenges in the field.

3,472 citations

Journal ArticleDOI
15 Jul 2005-Science
TL;DR: Magnetoelectric multiferroics combine ferromagnetic magnetization and ferroelectricity in the same phase and have tremendous potential for applications, not only because they possess the properties of both parent phenomena, but also because coupling between ferromagnetism and electric polarization can lead to additional novel effects as discussed by the authors.
Abstract: Magnetoelectric multiferroics combine ferromagnetism (a spontaneous magnetization that can be switched by a magnetic field) and ferroelectricity (a spontaneous electric polarization that can be switched by an electric field) in the same phase They have tremendous potential for applications, not only because they possess the properties of both parent phenomena, but also because coupling between ferromagnetism and ferroelectricity can lead to additional novel effects In their Perspective, Spaldin and Fiebig discuss the factors behind the recent resurgence of interest in magnetoelectric multiferroics, describe some exciting results emerging from the current research activities, and point to important challenges and directions for future work

2,523 citations

Journal ArticleDOI
TL;DR: In this paper, the coupling between the ferroelectric and magnetic order parameters in the magnetoelectric multiferroic was analyzed using density functional theory within the local spin density approximation (LSDA) and the $\mathrm{LSDA}+\mathm{U}$ method.
Abstract: We analyze the coupling between the ferroelectric and magnetic order parameters in the magnetoelectric multiferroic $\mathrm{Bi}\mathrm{Fe}{\mathrm{O}}_{3}$ using density functional theory within the local spin density approximation (LSDA) and the $\mathrm{LSDA}+\mathrm{U}$ method. We show that weak ferromagnetism of the Dzyaloshinskii-Moriya type occurs in this material, and we analyze the coupling between the resulting magnetization and the structural distortions. We explore the possibility of electric-field-induced magnetization reversal and show that, although it is unlikely to be realized in $\mathrm{Bi}\mathrm{Fe}{\mathrm{O}}_{3}$, it is not in general impossible. Finally, we outline the conditions that must be fulfilled to achieve switching of the magnetization using an electric field.

1,242 citations

Journal ArticleDOI
TL;DR: The observation of room-temperature electronic conductivity at ferroelectric domain walls in the insulating multiferroic BiFeO(3) shows that the conductivity correlates with structurally driven changes in both the electrostatic potential and the local electronic structure, which shows a decrease in the bandgap at the domain wall.
Abstract: Domain walls may play an important role in future electronic devices, given their small size as well as the fact that their location can be controlled. Here, we report the observation of room-temperature electronic conductivity at ferroelectric domain walls in the insulating multiferroic BiFeO3. The origin and nature of the observed conductivity are probed using a combination of conductive atomic force microscopy, high-resolution transmission electron microscopy and first-principles density functional computations. Our analyses indicate that the conductivity correlates with structurally driven changes in both the electrostatic potential and the local electronic structure, which shows a decrease in the bandgap at the domain wall. Additionally, we demonstrate the potential for device applications of such conducting nanoscale features. Domain walls may be important in future electronic devices, given their small size as well as the fact that their location can be controlled. In the case of insulating multiferroic oxides, domain walls are now discovered to be electrically conductive, suggesting their possible use in logic and memory applications.

1,208 citations


Cited by
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Journal ArticleDOI

[...]

08 Dec 2001-BMJ
TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

33,785 citations

Journal ArticleDOI
01 Apr 1988-Nature
TL;DR: In this paper, a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) is presented.
Abstract: Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

9,929 citations

Journal ArticleDOI
10 Mar 1970

8,159 citations

Journal ArticleDOI
17 Aug 2006-Nature
TL;DR: A ferroelectric crystal exhibits a stable and switchable electrical polarization that is manifested in the form of cooperative atomic displacements that arises through the quantum mechanical phenomenon of exchange.
Abstract: A ferroelectric crystal exhibits a stable and switchable electrical polarization that is manifested in the form of cooperative atomic displacements. A ferromagnetic crystal exhibits a stable and switchable magnetization that arises through the quantum mechanical phenomenon of exchange. There are very few 'multiferroic' materials that exhibit both of these properties, but the 'magnetoelectric' coupling of magnetic and electrical properties is a more general and widespread phenomenon. Although work in this area can be traced back to pioneering research in the 1950s and 1960s, there has been a recent resurgence of interest driven by long-term technological aspirations.

6,813 citations