Optimized fabrication of high-quality La_0.67Sr_0.33MnO₃ thin films considering all essential characteristics

Abstract

In this paper, an overview of the fabrication and properties of high-quality La0.67Sr0.33MnO3 (LSMO) thin films is given. A high-quality LSMO film combines a smooth surface morphology with a large magnetization and a small residual resistivity, while avoiding precipitates and surface segregation. In the literature, typically only a few of these issues are adressed. We therefore present a thorough characterization of our films, which were grown by pulsed laser deposition. The films were characterized with reflection high energy electron diffraction, atomic force microscopy, x-ray diffraction, magnetization and transport measurements, x-ray photoelectron spectroscopy and scanning transmission electron microscopy. The films have a saturation magnetization of 4.0 µB/Mn, a Curie temperature of 350 K and a residual resistivity of 60 µΩ cm. These results indicate that high-quality films, combining both large magnetization and small residual resistivity, were realized. A comparison between different samples presented in the literature shows that focussing on a single property is insufficient for the optimization of the deposition process. For high-quality films, all properties have to be adressed. For LSMO devices, the thin-film quality is crucial for the device performance. Therefore, this research is important for the application of LSMO in devices.

Epitaxial growth and properties of La0.7Sr0.3MnO3 thin films with micrometer wide atomic terraces

“…The step height is ~4 Å, which is equal to the height of one ML LSMO film in (100) direction. The terraces are ~3 µm wide, which are extraordinarily wide compared to several hundred nm in previous reports [12,15]. We believe that such extraordinarily wide terraces in LSMO can be attributed to the wide terraces of the annealed STO substrates prior to the LSMO growth (figure 1b).…”

“…As single terraces of ferromagnetic films with desired spin structures have the potential to create future spintronics devices, the atomic level control of the magnetic oxide thin films with wide atomic terraces is emergent. However, in previous reports, the terraces of these LSMO films are only several hundred nanometers wide [12,15] and the study of epitaxial LSMO films with micrometer wide atomic terraces has been lacking.In this letter, we report the growth of LSMO films with extraordinarily wide atomic terraces of more than 2 µm on STO (100) intensity shows a minimum value, which indicates the growth of an half ML LSMO film. Then the RHEED intensity starts to increase and reaches a maximum value at ~249 seconds and this indicates the growth of a full ML film.…”

“…Regarding the synthesis of thin LSMO films, pulsed laser deposition (PLD) has been found to be a promising method to achieve high quality films with atomic scale variations [11][12][13][14]. Common to strongly correlated oxide materials, the intriguing magnetic and electron transport properties of LSMO are intimately related to the spin-lattice-charge couplings, which are sensitive to strain, growth condition, and the thickness of the films [14,15]. For example, the magnetic anisotropy of LSMO has been shown to be in-plane when it is grown on SrTiO 3 (STO) substrates but out-of plane on LaAlO 3 (LAO) substrates [16,17].…”

High-Temperature Magnetic Insulating Phase in UltrathinLa0.67Sr0.33MnO3Films

“…LSMO thin films were grown on oxygen annealed STO (110) substrates by pulsed laser deposition (PLD), from a stoichiometric target in an oxygen background pressure of 0.27 mbar with a laser fluence of 2 J/cm 2 and at a substrate temperature of 780 • C, as previously optimized for LSMO growth on STO (001) [16,23]. After annealing the SrTiO 3 (STO) (110) substrates for 1 hour at 950 • C in a 1 bar oxygen atmosphere, smooth terraces with straight stepedges and half unit cell step height (2.7Å) were observed, using atomic force microscopy (AFM) [35].…”

Characterization of Electrical Transport in Lsmo with Enhanced Temperature of Metal-Insulator Transition

“…1 The resistivity in the lowest temperature range (below T 0 ≈ 20 K) exhibits essentially constant value of the residual resistivity ρ 0 , which is determined mainly by temperature independent scattering on impurities, defects, grain boundaries or domain walls. The typical value of ρ 0 is in the range of 100-200 µΩcm and it is about two times higher than ρ 0 of the single crystal [1] or of the high quality LSMO thin films [5]. In the temperature range T 0 −T 1 (range 20-220 K) the resistivity data follows the T 2 dependence.…”