La
                Mn
                  O
                  3
                ∕
                Sr
                Mn
                  O
                  3
           interfaces with coupled charge-spin-orbital modulation

Yamada, Hiroyuki; Kawasaki, Masashi; Lottermoser, Thomas; Arima, T.; Tokura, Y.

doi:10.1063/1.2266863

Cited by 91 publications

(103 citation statements)

References 16 publications

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“…6,12,13,14 However, the magnetization ( M  ) induced at a single interface is often too small to be detected by conventional tools and it is hard to characterize the cross-coupling of M  with electric polarization ( P  ), such as magneto-electric effects. One of the neat ways to amplify the effect is making superlattices to multiply the signal.…”

Section: Magneto-electric Coupling In Tricolor Superlatticesmentioning

confidence: 99%

Emergent phenomena at oxide interfaces

et al. 2012

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BASIC NOTIONSTransition metal oxides (TMOs) are an ideal arena for the study of electronic correlations because the s-electrons of the transition metal ions are removed and transferred to oxygen ions, and hence the strongly correlated d-electrons determine their physical properties such as electrical transport, magnetism, optical response, thermal conductivity, and superconductivity. These electron correlations prohibit the double occupancy of metal sites and induce a local entanglement of charge, spin, and orbital degrees of freedom. This gives rise to a variety of phenomena, e.g., Mott insulators, various charge/spin/orbital orderings, metal-insulator transitions, multiferroics, and superconductivity. 1 In recent years, there has been a burst of activity to manipulate these phenomena, as well as create new ones, using oxide heterostructures. 2 Most fundamental to understanding the physical properties of TMOs is the concept of symmetry of the order parameter. As Landau recognized, the essence of phase transitions is the change of the symmetry. For example, ferromagnetic ordering breaks the rotational symmetry in spin space, i.e., the ordered phase has lower symmetry than the Hamiltonian of the system. There are three most important symmetries to be considered here. (i) Spatial inversion (I), defined as r  -r. In the case of an insulator, breaking this symmetry can lead to spontaneous electric SLAC-PUB-14626 SIMES,

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Section: Magneto-electric Coupling In Tricolor Superlatticesmentioning

confidence: 99%

Emergent phenomena at oxide interfaces

et al. 2012

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“…This effect has been attributed to deteriorated magnetic properties of the manganite layer at the interface, a so-called ''dead layer,'' the origin of which is still not well understood [4,5]. Modified electronic and orbital structures at the interface [6,7] could be at the origin of the dead layer problem. In this Letter, we examine the possibility of manipulating the spin structure of the dead layer through the orbital reconstruction at the interface.…”

mentioning

confidence: 99%

Electronic and Magnetic Reconstructions inLa0.7Sr0.3MnO3/SrTiO3Heterostructures: A Case of Enhanced Interlayer Coupling Controlled by the Interface

et al. 2011

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=SrTiO 3 epitaxial heterostructures. Combined aberration-corrected microscopy and electron-energy-loss spectroscopy evidence charge transfer to the empty conduction band of the titanate. Ti d electrons interact via superexchange with Mn, giving rise to a Ti magnetic moment as demonstrated by x-ray magnetic circular dichroism. This induced magnetic moment in the SrTiO 3 controls the bulk magnetic and transport properties of the superlattices when the titanate layer thickness is below 1 nm. DOI: 10.1103/PhysRevLett.106.147205 PACS numbers: 75.70.Ài, 73.21.Cd, 75.47.Gk Among correlated electron systems, La 0:7 Sr 0:3 MnO 3 (LSMO) has been extensively studied as a possible source of spin-polarized electrons at room temperature [1]. The large values of tunneling magnetoresistance reported for LSMO=SrTiO 3 (STO)/LSMO tunnel junctions at a low temperature drop way below the Curie temperature of the magnetic electrodes, suggesting that a depolarization of the injected current may occur at the interface [2,3]. This effect has been attributed to deteriorated magnetic properties of the manganite layer at the interface, a so-called ''dead layer,'' the origin of which is still not well understood [4,5]. Modified electronic and orbital structures at the interface [6,7] could be at the origin of the dead layer problem. In this Letter, we examine the possibility of manipulating the spin structure of the dead layer through the orbital reconstruction at the interface.The origin of novel electronic states at the interface has been discussed in terms of the combined effect of epitaxial strain and the electronic and orbital reconstruction resulting from symmetry breaking [8][9][10]. Since in these correlated oxides spin ordering is largely determined by the orbital structure through Goodenough-Kanamori rules [11,12], the modified bonding at the interface determines its magnetic structure. This is the case for the ferromagnetic state reported to occur at the interface between nonferromagnetic LaFeO 3 and LaCrO 3 [13] and is also the origin of a ferromagnetic moment found in Cu at cuprate/manganite heterostructures [14,15] Here we show that manganite layers are magnetically coupled in LSMO/STO superlattices when the STO layer is thinner than 1 nm, which gives rise to very significant changes of magnetic and conducting properties. We have examined the electronic and magnetic structure of the LSMO/STO interface and found a magnetic moment induced at the Ti, resulting from the orbital reconstruction, which couples magnetically the LSMO layers. This finding constitutes direct evidence on how macroscopic properties of a heterostructure may be controlled by the interface orbital and spin reconstruction.Using a high-pressure pure oxygen sputtering technique, we have grown two series of ½LSMO M =STO N 8 superlattices consisting of 8 bilayers of M LSMO unit cells (u.c.) and N STO u.c., on (100) STO substrates. In the first series of samples, the LSMO thickness was fixed at M ¼ 6, thin enough to highlight the interface effects, with N STO ...

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“…In the case of LMO/SMO SLs the two materials widely change their behavior with respect to bulk. So, while in bulk the e g levels of SMO are empty and LMO presents in-plane (x 2 −r 2 )/(y 2 −r 2 ) orbital order, at SMO/LMO interfaces strain and electronic reconstruction are expected to modify orbital population and ordering in both components [11,12]. We have determined the orbital and magnetic properties of (SMO) n /(LMO) 2n SLs with n = 1, 5, 8, by measuring x-ray linear dichroism (XLD) and magnetic circular dichroism (XMCD) in x-ray absorption spectra (XAS) at the Mn L 2,3 edge.…”

mentioning

confidence: 99%

Evolution of magnetic phases and orbital occupation in(SrMnO3)n/(LaMnO3
Aruta¹,
Adamo
²
,
Galdi
³

et al. 2009
Phys. Rev. B
68
2
50
0
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The magnetic and electronic modifications induced at the interfaces in (SrMnO3)n/(LaMnO3)2n superlattices have been investigated by linear and circular magnetic dichroism in the Mn L2,3 x-ray absorption spectra. Together with theoretical calculations, our data demonstrate that the charge redistribution across interfaces favors in-plane ferromagnetic (FM) order and eg(x 2 − y 2 ) orbital occupation, in agreement with the average strain. Far from interfaces, inside LaMnO3, electron localization and local strain favor antiferromagnetism (AFM) and eg(3z 2 − r 2 ) orbital occupation. For n = 1 the high density of interfacial planes ultimately leads to dominant FM order forcing the residual AFM phase to be in-plane too, while for n ≥ 5 the FM layers are separated by AFM regions having out-of-plane spin orientation.PACS numbers: 75.47. Lx, 78.70.Dm, 72.10.Di, 73.21.Cd, Interfaces between different transition metal oxides (TMO) have been widely demonstrated to be sources of interesting and unexpected electronic and magnetic properties.Metallic conductivity arises, for example, at the interface between two insulators, such as LaAlO 3 /SrTiO 3 [1] and LaTiO 3 /SrTiO 3 [2], while ferromagnetism (FM) occurs at the interface between the antiferromagnet (AFM) CaMnO 3 and the paramagnet CaRuO 3 [3]. In this context, strain driven spin-orbital coupled states arising in manganites make the interfaces between these compounds very interesting for engineering unique collective states. As a matter of fact, a certain amount of theoretical and experimental studies on superlattices (SLs) composed by the two AFM insulators, SrMnO 3 (SMO) and LaMnO 3 (LMO), appeared in literature during the last years [4,5,6,7,8,9,10,11,12]. The ordered sequence of the atomic layers in the digital SMO/LMO SLs [4,5], together with the electronic reconstruction arising from the interfacial Mn 3+ /Mn 4+ mixed valence, give rise to peculiar transport, magnetic and orbital properties, when different layering and strain conditions occur. In the particular case of (SMO) n /(LMO) 2n the La:Sr ratio is 2:1, in analogy with the optimal composition of La 2/3 Sr 1/3 MnO 3 (LSMO). In such a case, the metal-insulator transition (MIT) and the magnetic properties depend on the thickness of the constituent blocks [4,5,6,7], although in a non trivial way. Indeed, saturation magnetization does not linearly decrease with n [4] and both fast and viscous spin populations are present, the latter associated to FM/AFM pinning [8]. Therefore, the development of the FM metallic phase at the interfaces is well established and the coexistance of the FM and AFM phases was inferred. However, the knowledge of the mutual dependence of the AFM and FM phases with n is still uncertain, but it could open further perspectives in the control of the low dimensional magnetic properties, thus in the engineering of the TMO magnetic heterostructures. In addition, as the role of interfacial Mn e g electrons is known to be important, the influence of strain and reduced dimensionality on the transpor...

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La Mn O 3 ∕ Sr Mn O 3 interfaces with coupled charge-spin-orbital modulation

Cited by 91 publications

References 16 publications

Emergent phenomena at oxide interfaces

Emergent phenomena at oxide interfaces

Electronic and Magnetic Reconstructions inLa0.7Sr0.3MnO3/SrTiO3Heterostructures: A Case of Enhanced Interlayer Coupling Controlled by the Interface

Evolution of magnetic phases and orbital occupation in(SrMnO3)n/(LaMnO3
Aruta¹,
Adamo
²
,
Galdi
³

et al. 2009
Phys. Rev. B
68
2
50
0
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La Mn O 3 ∕ Sr Mn O 3 interfaces with coupled charge-spin-orbital modulation

Cited by 91 publications

References 16 publications

Emergent phenomena at oxide interfaces

Emergent phenomena at oxide interfaces

Electronic and Magnetic Reconstructions inLa0.7Sr0.3MnO3/SrTiO3Heterostructures: A Case of Enhanced Interlayer Coupling Controlled by the Interface

Evolution of magnetic phases and orbital occupation in(SrMnO3)n/(LaMnO3Aruta1, Adamo2, Galdi3 et al. 2009Phys. Rev. B682500View full textAdd to dashboardCite

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Evolution of magnetic phases and orbital occupation in(SrMnO3)n/(LaMnO3
Aruta¹,
Adamo
²
,
Galdi
³

et al. 2009
Phys. Rev. B
68
2
50
0
View full text Add to dashboard Cite