Thickness-dependent magnetic and electrical transport properties of epitaxial La0.7Sr0.3CoO3 films

Li, Binzhi; Chopdekar, Rajesh V.; Kane, Alexander M.; Hoke, Kyle; N’Diaye, Alpha T.; Arenholz, Elke; Takamura, Yayoi

doi:10.1063/1.4979921

Cited by 9 publications

(16 citation statements)

References 27 publications

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“…These spectral features are more pronounced at the Co-L 2 edge (shown in detail in figure S5) where there is a gradual decrease in the higher energy B peak of the L 2 doublet feature. This trend towards the Co 3+ valence state was also observed in ultrathin LSCO films grown on LSAT substrates, and thus may be characteristic of the LSCO/air interface [16]. The shape of the Co-XMCD signal remains largely unchanged for all the LSMO/LSCO SLs with the exception of the m = 6 SL which shows a shift in the energy of the maximum Co-XMCD signal to ~0.…”

Section: Maximum Of Dρ(t) Dtsupporting

confidence: 59%

“…The metal/ insulator transition temperature, T MI , can be defined as the . t * (LSMO) and t * (LSCO) refer to literature data of the critical thickness below which LSMO and LSCO single layer films display degraded magnetization and conductivity [16,[30][31][32][33].…”

Section: Resultsmentioning

confidence: 99%

“…The relative magnitude of the XMCD values scale approximately in a 4:1 ratio of LSMO:LSCO as in their bulk phases [6,8] and both the Mnand Co-XMCD values, proportional to the atomic magnetic moment, share the same trend with decreasing sublayer thickness ( figure 3(b)). Previous studies on ultrathin La 1−x Sr x CoO 3 [15,16,29] and LSMO [30][31][32][33] films grown on SrTiO 3 (STO) and LSAT substrates have shown a similar abrupt degradation in the magnetization and conductivity once the film thickness drops below a critical thickness, t * . For LSMO films on both types of substrates, t * was found to be on the order of 10-13 u.c.…”

Section: Maximum Of Dρ(t) Dtmentioning

confidence: 85%

“…This result supports the conclusion of the resonant XRR data of limited chemical intermixing at the LSMO/LSCO interfaces and the formation of a well-defined SL structure. Moreover, these LSMO/LSCO SLs with ultrathin sublayers contrast strongly with ultrathin LSMO and LSCO single layers which also show purely insulating behavior [15,16,[29][30][31][32].…”

Section: Maximum Of Dρ(t) Dtmentioning

confidence: 97%

“…[30][31][32][33], and for LSCO films on LSAT and STO substrates, t * was 20 u.c. and 39 u.c., respectively [15,16,29]. The t * values for single layer LSMO and LSCO films grown on LSAT substrates are included as vertical dashed lines in figure 3(b).…”

Section: Maximum Of Dρ(t) Dtmentioning

confidence: 99%

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Engineered superlattices with crossover from decoupled to synthetic ferromagnetic behavior

Chopdekar¹,

Malik²,

Kane³

et al. 2017

J. Phys.: Condens. Matter

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TitleEngineered superlattices with crossover from decoupled to synthetic ferromagnetic behavior IntroductionDue to the strong coupling between the charge, spin, orbital, and lattice degrees of freedom, perovskite oxides with the chemical formula ABO 3 display a wide range of technologically relevant properties including ferromagnetism, ferroelectricity, and superconductivity [1]. Modern thin film growth techniques such as pulsed laser deposition (PLD) offer atomic scale control of the chemical composition, structural properties, and thickness of sublayers, and therefore have enabled the engineering of artificial composite materials which display emergent properties which differ from those of the constituent materials [2,3]. In these systems, interfacial interactions such as structural effects (i.e. breaking the 3D symmetry of the material, epitaxial strain, and modifications of the inherent BO 6 octahedral tilts/rotations), chemical effects (i.e. atomic intermixing), electronic effects (i.e. electronic/orbital reconstruction, charge transfer), and magnetic effects (i.e. exchange interactions, finite size effects associated with 2D layers) become important [4,5]. The competition between multiple interactions places a great challenge on our ability to understand and predict the resulting functional properties, and ultimately to exploit the emergent properties in applications.In this work, we explore the extent of interfacial interactions occurring in superlattices (SLs) composed of two ferromagnetic (FM) and metallic perovskite oxides, La 0.7 Sr 0. AbstractThe extent of interfacial charge transfer and the resulting impact on magnetic interactions were investigated as a function of sublayer thickness in La 0.7 Sr 0.3 MnO 3 /La 0.7 Sr 0.3 CoO 3 ferromagnetic superlattices. Element-specific soft x-ray magnetic spectroscopy reveals that the electronic structure is altered within 5-6 unit cells of the chemical interface, and can lead to a synthetic ferromagnet with strong magnetic coupling between the sublayers. The saturation magnetization and coercivity depends sensitively on the sublayer thickness due to the length scale of this interfacial effect. For larger sublayer thicknesses, the La 0.7 Sr 0.3 MnO 3 and La 0.7 Sr 0.3 CoO 3 sublayers are magnetically decoupled, displaying two independent magnetic transitions with little sublayer thickness dependence. These results demonstrate how interfacial phenomena at perovskite oxide interfaces can be used to tailor their functional properties at the atomic scale.

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Section: Maximum Of Dρ(t) Dtsupporting

confidence: 59%

Section: Resultsmentioning

confidence: 99%

Section: Maximum Of Dρ(t) Dtmentioning

confidence: 85%

Section: Maximum Of Dρ(t) Dtmentioning

confidence: 97%

Section: Maximum Of Dρ(t) Dtmentioning

confidence: 99%

See 3 more Smart Citations

Engineered superlattices with crossover from decoupled to synthetic ferromagnetic behavior

Chopdekar¹,

Malik²,

Kane³

et al. 2017

J. Phys.: Condens. Matter

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Spray-pyrolysis deposited La1−xSrxCoO3 thin films for potential non-volatile memory applications

2020

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In this work thin films of the La1-xSrxCoO3 (0.05 < x < 0.26) compound were grown, employing the so-called spray pyrolysis process. The as-grown thin films exhibit polycrystalline microstructure, with uniform grain size distribution, and observable porosity. Regarding their electrical transport properties, the produced thin films show semiconducting-like behavior, regardless the Sr doping level, which is most likely due to both the oxygen deficiencies and the grainy nature of the films. Furthermore, room temperature current-voltage (I-V) measurements reveal stable resistance switching behavior, which is well explained in terms of space-charge limited conduction mechanism. The presented experimental results provide essential evidence regarding the engagement of low cost, industrial-scale methods of growing perovskite transition metal oxide thin films, for potential applications in random access memory devices.

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Hydrogen-Induced Topotactic Phase Transformations of Cobaltite Thin Films

Feng,

Li,

Zhang

et al. 2024

J. Phys. Chem. C

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Manipulating physical properties through ion migration in complex oxide thin films is an emerging research direction to achieve tunable materials for advanced applications. While the reduction of complex oxides has been widely reported, few reports exist on the modulation of physical properties through a direct hydrogenation process. Here, we report an unusual mechanism for hydrogen-induced topotactic phase transitions in perovskite La 0.7 Sr 0.3 CoO 3 thin films. Hydrogenation is performed upon annealing in a pure hydrogen gas environment, offering a direct understanding of the role that hydrogen plays at the atomic scale in these transitions. Topotactic phase transformations from the perovskite (P) to hydrogenated-brownmillerite (H-BM) phase can be induced at temperatures as low as 220 °C, while at higher hydrogenation temperatures (320−400 °C), the progression toward more reduced phases is hindered. Density functional theory calculations suggest that hydroxyl bonds are formed with the introduction of hydrogen ions, which lower the formation energy of oxygen vacancies of the neighboring oxygen, enabling the transition from the P to H-BM phase at low temperatures. Furthermore, the impact on the magnetic and electronic properties of the hydrogenation temperature is investigated. Our research provides a potential pathway for utilizing hydrogen as a basis for low-temperature modulation of complex oxide thin films, with potential applications in neuromorphic computing.

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Thickness-dependent magnetic and electrical transport properties of epitaxial La0.7Sr0.3CoO3 films

Cited by 9 publications

References 27 publications

Engineered superlattices with crossover from decoupled to synthetic ferromagnetic behavior

Engineered superlattices with crossover from decoupled to synthetic ferromagnetic behavior

Spray-pyrolysis deposited La1−xSrxCoO3 thin films for potential non-volatile memory applications

Hydrogen-Induced Topotactic Phase Transformations of Cobaltite Thin Films

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