Neutron-diffraction study of<i>R</i><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">NiO</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>(<i>R</i>=La,Pr,Nd,Sm): Electronically induced structural changes across the metal-insulator transition

García-Muñoz, J. L.; Rodrı́guez-Carvajal, J.; Lacorre, P.; Torrance, J. B.

doi:10.1103/physrevb.46.4414

Cited by 507 publications

(379 citation statements)

References 19 publications

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“…During the thermally driven phase transition in SNO, the NiO 6 octahedron buckles at below metal-insulator transition (MIT) temperature, which reduces the orbital overlapping and renders an insulating phase (Fig. 1a) 15 . Charge disproportionation is mostly proposed as the cause for SNO's insulating phase (Fig.…”

Section: Resultsmentioning

confidence: 99%

Colossal resistance switching and band gap modulation in a perovskite nickelate by electron doping

2014

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The electronic properties of correlated oxides are exceptionally sensitive to the orbital occupancy of electrons. Here we report an electron doping strategy via a chemical route, where interstitial dopants (for example, hydrogen) can be reversibly intercalated, realizing a sharp phase transition in a model correlated perovskite nickelate SmNiO 3 . The electron configuration of e g orbital of Ni 3 þ t 6 2g e 1 g in SmNiO 3 is modified by injecting and anchoring an extra electron, forming a strongly correlated Ni 2 þ t 6 2g e 2 g structure leading to the emergence of a new insulating phase. A reversible resistivity modulation greater than eight orders of magnitude is demonstrated at room temperature. A solid-state room temperature nonvolatile proton-gated phase-change transistor is demonstrated based on this principle, which may inform new materials design for correlated oxide devices. Electron doping-driven phase transition accompanied by large conductance changes and band gap modulation opens up new directions to explore emerging electronic and photonic devices with correlated oxide systems.

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Section: Resultsmentioning

confidence: 99%

Colossal resistance switching and band gap modulation in a perovskite nickelate by electron doping

2014

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“…In bulk, LaNiO 3 (LNO) exhibits robust octahedral rotations leading to θ = 165.2 • along all < 001 > directions, 14 with an a − a − a − rotation pattern. 15 In contrast, bulk SrMnO 3 (SMO) is a cubic perovskite (a 0 a 0 a 0 ) lacking octahedral rotations (θ = 180 • ).…”

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confidence: 99%

Control of octahedral rotations in (LaNiO3)n/(SrMnO

May

Smith²,

Kim³

et al. 2011

Phys. Rev. B

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Oxygen octahedral rotations have been measured in short-period (LaNiO3)n/(SrMnO3)m superlattices using synchrotron diffraction. The in-plane and out-of-plane bond angles and lengths are found to systematically vary with superlattice composition. Rotations are suppressed in structures with m > n, producing a nearly cubic form of LaNiO3. Large rotations are present in structures with m < n, leading to reduced bond angles in SrMnO3. The metal-oxygen-metal bond lengths decrease as rotations are reduced, in contrast to behavior previously observed in strained, single layer films. This result demonstrates that superlattice structures can be used to stabilize non-equilibrium octahedral behavior in a manner distinct from epitaxial strain, providing a novel means to engineer the electronic and ferroic properties of oxide heterostructures.The ABO 3 perovskite oxides exhibit an array of physical properties making them attractive for applications in electronics and energy conversion. 1-3 Recent work has demonstrated that the functionality of these materials can be further expanded through the formation of superlattices, which can exhibit enhanced properties compared to bulk compounds. While the majority of work in this field has focused on the electronic and ferroic properties of oxide superlattices, 4-9 the impact of heterointerfaces on the local atomic structure has received less attention. 10-13 Of particular importance are the rotations and distortions of the BO 6 octahedra, which determine the B-O-B bond angles (θ) and B-O bond lengths (d). As both θ and d couple to the electronic bandwidth, a quantitative understanding of how octahedral rotations are modified in short-period superlattices is necessary in order to control novel electronic phenomena in oxide heterostructures.Motivated by the question of what octahedral behavior is stabilized at the interface between two structurally dissimilar perovskites, we have investigated the bond angles in a systematic series of (LaNiO 3 ) n /(SrMnO 3 ) 2 superlattices. In bulk, LaNiO 3 (LNO) exhibits robust octahedral rotations leading to θ = 165.2 • along all < 001 > directions, 14 with an a − a − a − rotation pattern. 15 In contrast, bulk SrMnO 3 (SMO) is a cubic perovskite (a 0 a 0 a 0 ) lacking octahedral rotations (θ = 180 • ). 16 Due to the short-period of the superlattices investigated and the geometric constraint requiring that the BO 6 octahedra maintain corner connectivity, the octahedral rotations remain coherent throughout the superlattices. We demonstrate that the in-plane and out-of-plane bond angles and lengths can be tuned by altering the superlattice composition [n/(n+m)], allowing for the stabilization of octahedral behavior that differs substantially from that found in bulk compounds.The (LNO) n /(SMO) m superlattices, herein referred to as LnSm, were deposited on SrTiO 3 substrates by ozoneassisted molecular beam epitaxy. 17 The sample thicknesses are between 200 and 215Å. Previous structural (00L) in three samples exhibiting distinct satellite peaks due to t...

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“…One of the models [36,84] is based on the emerging of the high-spin-low-spin transition of Fe 3+ ions under high pressures. In another model developed for nickelates [85] it is assumed that the insulator-metal transition is due to a closing of the charge-transfer gap between the oxygen p orbitals and the iron d orbitals. The authors use the similarity of the structural changes accompanying the insulator-metal transition in BiFeO 3 and RNiO 3 (R = Pr and Nd) as a main proof of the above conclusion.…”

Section: Relation Of the Insulator-metal Transition With The Lone Paimentioning

confidence: 99%

Magnetoelectric Ordering of BiFeO3 from the Perspective of Crystal Chemistry

Волкова

Marinin

2011

J Supercond Nov Magn

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In this paper we examine the role of crystal chemistry factors in creating conditions for formation of magnetoelectric ordering in BiFeO 3 . It is generally accepted that the main reason of the ferroelectric distortion in BiFeO 3 is concerned with a stereochemical activity of the Bi lone pair. However, the lone pair is stereochemically active in the paraelectric orthorhombic ß-phase as well. We demonstrate that a crucial role in emerging of phase transitions of the metal-insulator, paraelectric-ferroelectric and magnetic disorder-order types belongs to the change of the degree of the lone pair stereochemical activity -its consecutive increase with the temperature decrease. Using the structural data, we calculated the sign and strength of magnetic couplings in BiFeO 3 in the range from 945º down to 25º С and found the couplings, which undergo the antiferromagneticferromagnetic transition with the temperature decrease and give rise to the antiferromagnetic ordering and its delay in regard to temperature, as compared to the ferroelectric ordering. We discuss the reasons of emerging of the spatially modulated spin structure and its suppression by doping with La 3+ .

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Neutron-diffraction study ofRNiO3(R=La,Pr,Nd,Sm): Electronically induced structural changes across the metal-insulator transition

Cited by 507 publications

References 19 publications

Colossal resistance switching and band gap modulation in a perovskite nickelate by electron doping

Colossal resistance switching and band gap modulation in a perovskite nickelate by electron doping

Control of octahedral rotations in (LaNiO3)n/(SrMnO

Magnetoelectric Ordering of BiFeO3 from the Perspective of Crystal Chemistry

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