32 The rapid progress was, in part, facilitated by experience developed in the (SrTiO 3) nSrO system. For instance, the first demonstration of the synthetically challenging superconducting (NdNiO 3) 5NdO phase by MBE 5 was published only three years after the first report of superconductivity in doped NdNiO 2. 22,25–29 Nonetheless, synthetic discoveries are often transferrable across material systems. ![]() ![]() 22–31 Many of these studies have investigated strontium titanate Ruddlesden–Popper phases with formula (SrTiO 3) nSrO as a comparatively simple model system with no charged monolayers, no octahedral rotations, and no volatile species. Nonetheless, synthesis demands precise calibration and the surface kinetics during film growth have proven counterintuitive, prompting detailed studies on Ruddlesden–Popper thin film synthesis. More specifically, the order in which precise doses of the species contained in each monolayer are supplied to the substrate can build up a targeted member of a homologous series. 17 TEM images of attempts to make bulk (SrTiO 3) nSrO phases with n > 3 show disordered syntactic intergrowths where n ranges from 2 to 8 18 because these phases are nearly degenerate in energy.Īccessing Ruddlesden–Popper phases with intermediate n (i.e., 4 < n < ∞ for nickelates, ruthenates, and titanates) in oxide systems or in other homologous series is possible using thin-film methods that exploit kinetics. This difficulty is particularly obtrusive to bulk synthesis methods for which n = 3 is the highest value of n that has been achieved in single-phase samples of (SrTiO 3) nSrO, 14 (SrRuO 3) nSrO, 15 (CaTiO 3) nCaO, 16 and (LaNiO 3) nLaO. 6,8–10 Attention to these series members is, at least in part, due to the amplified difficulty of synthesizing Ruddlesden–Popper phases with increasing n (excluding the n = ∞ perovskite phase). 12,13 Interestingly, research disproportionately focuses on the n = 1 and n = 2 members of the Ruddlesden–Popper series with chemical formula ( ABO 3) 1 AO 1–4,6,7,11 and ( ABO 3) 2 AO. These perovskite-related phases demonstrate diverse properties, including high- T c and unconventional superconductivity, 1–5 colossal magnetoresistance, 6 exotic Mott instability, 7 metamagnetism, 8,9 electronic nematicity, 10,11 and low-loss tunable dielectricity. This detailed synthetic study of high n, metastable Ruddlesden–Popper phases is pertinent to a variety of fields from quantum materials to tunable dielectrics.Įver since the discovery of high-transition temperature (high- T c) superconductivity in doped La 2CuO 4, 1 Ruddlesden–Popper oxides with formula ( ABO 3) n AO have been an important class of compounds for condensed matter physics. At the optimal growth temperature, we demonstrate that as much as 33% barium can homogeneously populate the A-site when films are grown on SrTiO 3 (001) substrates, whereas up to 60% barium can be accommodated in films grown on TbScO 3 (110) substrates, which we attribute to the difference in strain. We proceed to investigate barium incorporation into the Ruddlesden–Popper structure, which is limited to a few percent in bulk, and we find that the amount of barium that can be incorporated depends on both the substrate temperature and the strain state of the film. The precision and consistency of the method described is demonstrated by the growth of an unprecedented (SrTiO 3) 50SrO epitaxial film. Help: Go to the Support page to view tutorials, find a crystal structure, participate in user forums, and to get technical help.We outline a method to synthesize ( ATiO 3) n AO Ruddlesden–Popper phases with high- n, where the A-site is a mixture of barium and strontium, by molecular-beam epitaxy. ![]() Quick tip: If your license key doesn't work, download and install the latest version of the software. Be sure to specify the version (Mac or Windows) plus the name of the software program(s) you want as there is a different license key for each one. Please include your Stanford ID number in the request. To get the license keys, please send a request to the Science Library using your email address. ![]() License keys: License keys are available to all current students, faculty, and staff at Stanford. Keep up-to-date with the latest software updates. After installing the software, you do not need to be connected to the Internet in order to use it. Both native Mac and Windows versions are available (but not Linux). Our current license expires February 28, 2023. We have a campus-wide site license for the CrystalMaker package that includes three software programs: CrystalMaker, CrystalDiffract, and SingleCrystal.
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