Modulated Structure of La2NiO4+δas a Mechanism of Oxygen Excess Accommodation

Structural study of lanthanum nickelate thin films deposited on different single crystal substrates

“…These structural changes would therefore be at the origin of different crystal structures reported in the literature. However, interesting results reported by Sayague´s et al [4] were to show that modulated structures of La 2 NiO 4þd can as well be formed for accommodating the oxygen excess. In this case, structures commensurately modulated along the a-or c-axes of the orthorhombic structure were observed by high-resolution TEM.…”

“…Refs. [3][4][5][6][7][8]). Besides fundamental aspects, several potential applications of the La 2 NiO 4þd compound are often mentioned in these studies.…”

Electronic Structure of Superoxygenated La2NiO4 Domains with Ordered Oxygen Interstitials

“…In the largest cell of LNO8-0 there are 208 occupied bands, in LCO8-0 there are 212. Here, for LNO we concentrate the investigations of the shorter cells, since they correspond best to the experimentally found periodicity of O-interstitials in LNO [11][12][13][14][15].…”

“…Superoxygenated La 2 NiO 4+δ is an oxygen ionic conductor at high temperature [1][2][3][4][5][6] with interesting electrochemical, thermo-mechanical properties and applications in fuel cells [7][8][9][10]. The gas of mobile oxygen interstitials (O i )at high temperate freeze below about 400K forming crystalline grains, as is observed by electron and neutron diffraction [11][12][13][14][15]. At lower temperature, below 200K, the electronic structure show the onset of spin and charge stripes i.e., one dimensional spin density waves (SDW) and charge density waves (CDW) [16][17][18][19][20] due to ordering of polarons [21].…”

VUV Pump and Probe of Phase Separation and Oxygen Interstitials in La2NiO4+y Using Spectromicroscopy

“…This is the case of doped La 2 NiO 4+y where, due to the large tensile misfit strain in the [La 2 O 2+y ], the mobility of oxygen interstitials is high. The latter is in fact an oxygen ion conductor at high temperature with high technological relevance [43][44][45][46][47][48][49][50]. Synchrotron radiation investigations of La 2 NiO 4+y [51,52] and La 2 CuO 4+y [53] have been performed using standard XANES, X-ray absorption near edge structure, [54][55][56][57][58] interpreted considering many body final states configurations, relevant in these strongly correlated oxides [59][60][61][62][63][64][65].…”