Structural, microstructural, and transport properties of highly oriented LaNiO3 thin films deposited on SrTiO3 (100) single crystal

Jenderka

Grundmann

et al. 2015

Phys. Status Solidi A

97 39286LaNiO 3 (LNO) thin films were grown using pulsed laser deposition. The c-axis, i.e., out-of-plane lattice parameter of the films was controlled reproducibly by using different substrate materials and by variation of oxygen partial pressure and growth temperature. The out-of-plane (c-axis) strain of LNO deposited on LaAlO 3 with increasing oxygen pressure changed from positive to negative. All the films show an excellent metallic conductivity with positive resistivity temperature coefficient. Lowest resistivity was about 300 mV cm. At high and low temperatures, the resistivity is explained by electron-phonon scattering and electron-electron interaction, respectively. In addition, the resistivity shows a clear dependence on the c-axis strain of LNO films. With increasing strain, the resistivity increases. However, this effect is much more pronounced for negative c-axis strain.Strain-dependent resistivity of LNO films on LAO at the indicated measurement temperatures. The inset is a typical AFM image of the LNO film surface.1 Introduction The conduction band of perovskite nickelates (RNiO 3 , where R ¼ rare earth) is formed by the overlap of the Ni 3d orbitals and the O 2p orbitals. Most perovskite nickelates exhibit a temperature-driven metal-toinsulator transition [1,2], which is related to the strongly distorted perovskite structure and the size of the rare-earth ion R [3, 4]. However, LaNiO 3 (LNO) is the only member that remains metallic down to the lowest temperatures [5]. For this reason, LNO is an excellent candidate for use as an electrode in oxide electronics, in particular at low temperature. The primitive cell of bulk LNO is rhombohedral with angle a ¼ 60.498. It is reasonably well approximated by a pseudocubic cell with a ¼ 0.3838 nm. Several efforts have been undertaken to prepare LNO thin films by sputtering [6], pulsed laser deposition (PLD) [7], molecular beam

Section: Resultssupporting

confidence: 88%

LaNiO₃ films with tunable out-of-plane lattice parameter and their strain-related electrical properties

Jenderka

Grundmann

et al. 2015

Phys. Status Solidi A

“…At high temperatures (100-300 K), the sheet resistance is linearly proportional to temperature due to dominant electron-phonon scattering, which corresponds well with the reported results on other LNO single films. 23 With the decreasing number of LNO unit cells in the SLs, insulating behavior appears. The metal-insulator transition has been reported in LNO ultra-thin films, in which the charge disproportionation with an accompanying symmetry change was considered the origin of this phenomenon.…”

Section: -3mentioning

confidence: 99%

Charge transfer-induced magnetic exchange bias and electron localization in (111)- and (001)-oriented LaNiO3/LaMnO3 superlattices

Applied Physics Letters

Barzola‐Quiquia

Yang

et al. 2017

High-quality lattice-matched LaNiO3/LaMnO3 superlattices with monolayer terrace structure have been grown on both (111)- and (001)-oriented SrTiO3 substrates by pulsed laser deposition. In contrast to the previously reported experiments, a magnetic exchange bias is observed that reproducibly occurs in both (111)- and (001)-oriented superlattices with the thin single layers of 5 and 7 unit cells, respectively. The exchange bias is theoretically explained by charge transfer-induced magnetic moments at Ni atoms. Furthermore, magnetization data at low temperature suggest two magnetic phases in the superlattices, with Néel temperature around 10 K. Electrical transport measurements reveal a metal-insulator transition with strong localization of electrons in the superlattices with the thin LaNiO3 layers of 4 unit cells, in which the electrical transport is dominated by two-dimensional variable range hopping.

“…All LNO single films show metallic conductivity in the measured temperature range from less than 50 K to 300 K. For modeling of conductivity of thick LNO films, see the former papers. 16,17 In the following, we discuss the extension of Ref. 16 to lower LNO thickness.…”

mentioning

confidence: 99%

Modeling the conductivity around the dimensionality-controlled metal-insulator transition in LaNiO3/LaAlO3 (100) superlattices

Applied Physics Letters

Jenderka

Bonholzer

et al. 2015