TY  - JOUR
AU  - Hareesh, Chavana
AU  - Ceretti, Monica
AU  - Papet, Philippe
AU  - Bosak, Alexeï
AU  - Meven, Martin
AU  - Paulus, Werner
TI  - Synthesis and Structural Characterization of Layered Ni$^{+1/+2}$ Oxides Obtained by Topotactic Oxygen Release on Nd$_{2−x}$Sr$_{x}$NiO$_{4−δ}$ Single Crystals
JO  - Crystals
VL  - 13
IS  - 12
SN  - 2073-4352
CY  - Basel
PB  - MDPI
M1  - FZJ-2024-01341
SP  - 1670 -
PY  - 2023
AB  - Layered nickelate oxides containing Ni$^{1+}$/Ni$^{2+}$ are isoelectronic to Cu$^{2+}$/Cu$^{3+}$ compounds and of present interest with respect to recent findings of superconductivity in a series of different compositions. It is thereby questionable why superconductivity is still rare to find in nickelates, compared to the much larger amount of superconducting cuprates. Anisotropic $d_{z^2}$ vs. $d_{x^2−y^2}$ orbital occupation as well as interface-induced superconductivity are two of the main advanced arguments. We are here interested in investigating the feasibility of synthesizing layered nickelate-type oxides, where the Ni$^{1+}$/Ni$^{2+}$ ratio can be tuned by oxygen and/or cation doping. Our strategy is to synthesize Sr-doped $n$ = 1 Ruddlesden–Popper type Nd$_{2−x}$Sr$_x$NiO$_{4+δ}$ single crystals, which are then reduced by H$_2$ gas, forming Nd$_{2−x}$Sr$_x$NiO$_{4−δ}$ via a topotactic oxygen release at moderate temperatures. We report here on structural studies carried out on single crystals by laboratory and synchrotron diffraction using pixel detectors. We evidence the general possibility to obtain reduced single crystals despite their increased orthorhombicity. This must be regarded as a milestone to obtain single crystalline nickelate oxides, which further on contain charge-ordering of Ni$^{1+}$/Ni$^{2+}$, opening the access towards anisotropic properties.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:001132741600001
DO  - DOI:10.3390/cryst13121670
UR  - https://juser.fz-juelich.de/record/1022220
ER  -