Orbital physics in transition-metal oxides from first-principles

Wu, Hua

doi:10.1016/j.commatsci.2015.09.018

Cited by 7 publications

(14 citation statements)

References 49 publications

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“…Rare-earth manganites with perovskite structure of the general composition of type Re1-xAxMnO3 where Re is a trivalent rare-earth ion such as La, Nd, Dy, Pr and A is a divalent alkaline-earth such as Ca, Sr or Ba has been received remarkable attention due to their unique physical properties as well as potential applications [1][2][3][4][5][6]. In addition, studies on these rare-earth manganites have revealed that colossal magnetoresistance (CMR) effect which is commonly attributed to the double-exchange (DE) mechanism is also suggested to be related to the Jahn-Teller (JT) effect and charge ordering (CO) [7].…”

Section: Introductionmentioning

confidence: 99%

Enhancement of Double-Exchange Mechanism in Charge-Ordered Pr0.75Na0.25MnO3 Ceramics by Cr Doped at Mn-Site

Zawawi¹,

Ibrahim²,

Shamsuddin³

2018

IJCRSET

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Charge ordered Pr0.75Na0.25Mn1-xCrxO3 (x = 0-0.04) ceramics has been investigated to study the effect of Cr doping on structure and electrical transport properties as well as surface morphology which synthesized using the solid-state reaction method. X-ray diffraction (XRD) analysis revealed the crystalline phase of all samples consists of essentially single phase and crystallized in an orthorhombic structure. The Cr doping were influence the lattice parameters and the unit cell volume suggestively due to the different of ionic radius between Mn 3+ ions and Cr 3+ ions. DC electrical resistance measurement showed that, the x = 0 sample exhibited an insulating behaviour down to the lower temperature. Interestingly, the metal-insulator (MI) transition temperature for x = 0.02 and x = 0.04 samples were found to be around TMI~120 K and TMI~122 K respectively indicating the enhancement of double-exchange (DE) mechanism as a result of weakening the Jahn-Teller (JT) effect which caused the charge ordered (CO) state to be weakened. scanning electron microscope (SEM) images of Pr0.75Na0.25Mn1-xCrxO3 compound showed the morphology of the samples were quite uniform suggestively due to the good crystalline nature.

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Section: Introductionmentioning

confidence: 99%

Enhancement of Double-Exchange Mechanism in Charge-Ordered Pr0.75Na0.25MnO3 Ceramics by Cr Doped at Mn-Site

Zawawi¹,

Ibrahim²,

Shamsuddin³

2018

IJCRSET

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“…1(a)]. Alternatively, a reduction from O h to D 4h symmetry (e.g., induced by a Jahn-Teller instability, as we discuss below), may lead to spin-orbital mixing between spectroscopic terms 5 A 1g and 3 E g away from (Dq/B) c ≈ 2.7, see Fig. 1(b).…”

Section: Introductionmentioning

confidence: 96%

“…Orbital degrees of freedom are an essential ingredient of the physics and chemistry of transition metal compounds [1][2][3][4][5]. The coupling of orbitals to spin, charge, or lattice determines many properties of solids and molecules.…”

Section: Introductionmentioning

confidence: 99%

“…For instance, in 4d/5d transition metals, where several energy scales (including spin-orbit coupling and crystal field) are comparable [27,28], the t 2g − e g mixing can not be generally ignored [29,30], which is relevant to predict magnetic excitations in heavy transition metal oxides. Alternatively, 5 T 2 , 3 T 1 , and 5 E in O h point symmetry [1]. Along the ordinate axis, the energy E is shown relative to the Racah parameter B.…”

Section: Introductionmentioning

confidence: 99%

“…coming from vibronic couplings and spin-orbit interactions. The Hamiltonian can be formally expressed in terms of irreducible representations A 2g (S = 1), 5 A 1g (S = 2), and 5 B 1g (S = 2), giving a total of 19 states for the full dimensionality of the |ψ i basis. The on-site Hamiltonian H S can be decomposed as…”

Section: Introductionmentioning

confidence: 99%

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Jahn-Teller states mixed by spin-orbit coupling in an electromagnetic field

Miñarro

Herranz²

2022

Phys. Rev. B

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Quasi‐Two‐Dimensional Ferromagnetic SrRuO₃ Grown by Pulsed Laser Deposition with Layer‐by‐Layer Growth Fashion

Deng

Liu

Hong

et al. 2022

Adv Materials Inter

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expansion increases the bandwidth and reduces the density of states (DOS) of the Fermi level, however, the strong orbital hybridization between Ru 4d and O 2p of SRO will enhance the DOS, resulting in ferromagnetic interaction and metallicity, and the Curie temperature (T c ) of bulk SRO as high as 160 K. [16,17] SRO also has good electrical conductivity, thermal property, and chemical inertia, and has a high lattice matching degree on a variety of commonly used substrates. [18,19] Recent research on SRO heterostructures and superlattices with ultra-thin SRO layer further show remarkable phenomena. Typical examples include the ferroelectric tunable topological Hall effect (THE), [20][21][22][23][24] skyrmion in BaTiO 3 /SrRuO 3 , [9] and spin chirality fluctuation in 2D SRO ferromagnets with perpendicular magnetic anisotropy. [25] Besides, SRO is also used extensively in the study of anomalous Hall effect (AHE). [8,9,26,27] In SRO, both the AHE and THE of the SRO/STO heterostructure show a strong SRO thickness (t SRO ) dependence. If the thickness is not accurate or uniform, areas with different thicknesses will be superimposed, resulting in an artificial THE signal. [28] Therefore, a layer-by-layer growth mode is desired to precisely regulate the thickness at the unit cell (u.c.) level.However, quite different from many perovskite oxides such as La 2/3 Sr 1/3 MnO 3 , LaCoO 3 , and SrTiO 3 , where a layerby-layer growth mode can persist for even 100 unit cells, the SRO usually quickly transits from layer-by-layer mode into step-flow mode. According to previous studies, when SRO thin film is grown on a TiO 2 -terminated (001) STO substrate, the terminated atomic layer changes from the B-site to the A-site in the first period, [29,30] resulting in the transition from 2D layerby-layer mode to step-flow mode. In step-flow growth mode, the RHEED intensity does not oscillate and remains stable, making the thickness of the films impossible to be intuitively monitored by RHEED. Therefore, it is difficult to accurately control the thickness of superlattices and multilayer films.In this paper, we report the exploration of layer-by-layer growth of SRO. The epitaxial SRO thin films and (SRO n /STO 5 ) 10 superlattices were grown on TiO 2 -terminated (001) STO substrates. The single TiO 2 -terminated (001) STO substrates were obtained through standard buffered oxide etch (BOE) One of the keys to the construction of metal oxide heterostructures is the short characteristic length scale, which requires controlled growth and interface engineering on an atomic level. At present, the growth mode of SrRuO 3 (SRO) thin films grown on TiO 2 -terminated (001) SrTiO 3 (STO) substrates usually transitions from 2D layer-by-layer to step-flow at the first few growth periods, which is not conducive to the construction of superlattices or multilayer films. In this paper, persistent layer-by-layer growth of SRO thin films is demonstrated by regulating the growth conditions. As a result, the thickness can be precisely controlled down to a sing...

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Orbital physics in transition-metal oxides from first-principles

Cited by 7 publications

References 49 publications

Enhancement of Double-Exchange Mechanism in Charge-Ordered Pr0.75Na0.25MnO3 Ceramics by Cr Doped at Mn-Site

Enhancement of Double-Exchange Mechanism in Charge-Ordered Pr0.75Na0.25MnO3 Ceramics by Cr Doped at Mn-Site

Jahn-Teller states mixed by spin-orbit coupling in an electromagnetic field

Quasi‐Two‐Dimensional Ferromagnetic SrRuO₃ Grown by Pulsed Laser Deposition with Layer‐by‐Layer Growth Fashion

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Orbital physics in transition-metal oxides from first-principles

Cited by 7 publications

References 49 publications

Enhancement of Double-Exchange Mechanism in Charge-Ordered Pr0.75Na0.25MnO3 Ceramics by Cr Doped at Mn-Site

Enhancement of Double-Exchange Mechanism in Charge-Ordered Pr0.75Na0.25MnO3 Ceramics by Cr Doped at Mn-Site

Jahn-Teller states mixed by spin-orbit coupling in an electromagnetic field

Quasi‐Two‐Dimensional Ferromagnetic SrRuO3 Grown by Pulsed Laser Deposition with Layer‐by‐Layer Growth Fashion

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Product

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Quasi‐Two‐Dimensional Ferromagnetic SrRuO₃ Grown by Pulsed Laser Deposition with Layer‐by‐Layer Growth Fashion