Moderate pressure synthesis of rare earth nickelate with metal–insulator transition using polymeric precursors

Napierala, Cecile; Lepoittevin, Christophe; Edely, Mathieu; Sauques, Laurent; Giovanelli, F.; Laffez, P.; VanTedeloo, G.

doi:10.1016/j.jssc.2010.04.019

Cited by 7 publications

(4 citation statements)

References 26 publications

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“…7 and our estimates for h and s. Although we do not here model case of chemical substitution, the phase stability diagrams in Fig. 7a and b appear to be consistent with the reported synthesis of oxygen-decient Nd 0.3 Sm 0.7 NiO 3Àd bulk powder samples by annealing at 20 bar O 2 and 1063 K. 31 It is important to note two potential limitations of our study pertaining to the general problem of such thermodynamic analyses applied to oxide phase formation in thin lm form. The rst is an inherent limitation: we do not account for interfacial reactions that may occur with an underlayer or substrate during the high pressure annealing processes.…”

Section: Discussionsupporting

confidence: 89%

High pressure synthesis of SmNiO3 thin films and implications for thermodynamics of the nickelates

Jaramillo

Schoofs

et al. 2013

J. Mater. Chem. C

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Section: Discussionsupporting

confidence: 89%

High pressure synthesis of SmNiO3 thin films and implications for thermodynamics of the nickelates

Jaramillo

Schoofs

et al. 2013

J. Mater. Chem. C

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“…The advantage of the sol-gel route is that precursor powders are ultra-fine so that their reactivity is much higher than that of binary oxides and carbonates at reduced temperatures due to the short diffusion path of the ions [11,21]; thus, in principle, synthesis can be carried out at lower temperatures and pressures. Nevertheless, for perovskite nickelates, while this approach does reduce the required pressure, it still involves heat treatment at temperatures greater than 1000 °C and under oxygen pressures as high as 200 bar [22].…”

Section: Introductionmentioning

confidence: 99%

Synthesis and characterization of bulk Nd1−xSrxNiO2 and Nd
Wang
¹
,
Zheng
²
,
E.
³

et al. 2020
Phys. Rev. Materials
123
6
72
0
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The recent reports of superconductivity in Nd1-xSrxNiO2/SrTiO3 heterostructures have reinvigorated interest in potential superconductivity of low-valence nickelates. Synthesis of Ni 1+ -containing compounds is notoriously difficult. In the current work, a combined sol-gel combustion and high-pressure annealing technique was employed to prepare polycrystalline perovskite Nd1-xSrxNiO3 (x = 0, 0.1 and 0.2). Metal nitrates and metal acetates were used as starting materials, and the latter were found to be superior to the former in terms of safety and reactivity. The Nd1-xSrxNiO3 compounds were subsequently reduced to Nd1-xSrxNiO2 using calcium hydride in a sealed, evacuated quartz tube. To understand the synthesis pathway, the evolution from NdNiO3 to NdNiO2 was monitored using in-situ synchrotron X-ray diffraction during the reduction process. Electrical transport properties were consistent with an insulatormetal transition occurring between x = 0 and 0.1 for Nd1-xSrxNiO3. Superconductivity was not observed in our bulk samples of Nd1-xSrxNiO2. Neutron diffraction experiments at 3 K and 300 K were performed on Nd0.9Sr0.1NiO2, in which no magnetic Bragg reflections were observed, and the results of structural Rietveld refinement are provided. Synthesis of Nd1-xSrxNiO3Nitrate method: Nd1-xSrxNiO3 (x = 0, 0.1 and 0.2) was synthesized via the citrate-nitrate autocombustion synthesis as described by Deganello et al. [23] Metal nitrates Nd(NO3)3•6H2O (Strem Chemicals, 99.999%), Ni(NO3)2 •6H2O (Sigma-Aldrich, 99.999%) and Sr(NO3)3 (Alfa Aesar, 99.97%) were used as starting materials. The metal nitrates were dissolved in a minimum amount of distilled water to obtain a clear solution. The exact concentrations of metal nitrates were determined by inductively coupled plasma mass spectrometry (ICP-MS) to account for variable levels of hydration in the starting materials. Stoichiometric amounts of nitrates were mixed in a beaker to get the desired Nd1-xSrxNiO3 (x = 0 to 0.2) precursor solutions. An aqueous solution of citric acid was then mixed with the precursor solutions at a molar ratio, citric acid to metal ions, of 1.2:1 at room temperature. The pH of the precursor solution was adjusted to ~ 7 by adding 30 wt. % aqueous NH3. The solution was slowly evaporated at 70 °C with continuous mechanical stirring, until a hardened gel was obtained. To carry out the gel decomposition under controlled conditions, the hardened gel was transferred to an alumina crucible, which was then put on a hot plate at 250 -300 °C. The gel first turned to black, and then ignited and underwent a vigorous self-sustaining combustion, yielding an ash product. The combusted powders were then fired at 800 °C for 12 h in an oxygen atmosphere at ambient pressure with a flow rate of 0.2 L/min. The resulting black powder was then ground and pressed into pellets with dimensions of 13 mm diameter and about 0.2 mm thickness. The pellets were subsequently fired at 1000 °C under 150-160 bar of oxygen pressure for 12 hours in a highpressure annealing furnace (Model...

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“…Using the sol–gel routes, Napierala et al have shown recently the possibility to synthetize a fully oxidized perovskite by using polymeric precursor associated with moderate pressure annealing (20 bar) at 1060 K. Analyses by transmission electronic microscopy led to the conclusion that the structure commonly obtained at 175 bar is perfectly observed in the sample prepared at 20 bar without major structural defects. The two types of samples (175 and 20 bar) exhibited equivalent thermochromic behavior and thermo-optical properties.…”

Section: Introductionmentioning

confidence: 99%

Mechanisms of Oxidation of NdNiO_3−δ Thermochromic Thin Films Synthesized by a Two-Step Method in Soft Conditions

et al. 2014

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Considering it is somewhat difficult to crystallize thermochromic nickelates through a soft process, a major challenge in NdNiO 3 crystallization is the stabilization of the Ni 3+ oxidation state against Ni 2+ . The aim of the present work was to understand why a soft annealing is sufficient while an oxygen high pressure (200 bar) is usually considered as required. Thin films of 300 nm have been deposited by reactive magnetron sputtering at room temperature and working pressure of 0.5, 4, and 7 Pa. The oxygen content of asdeposited and annealed films was estimated by Rutherford backscattering spectrometry, whereas the nickel oxidation state evolution was followed by X-ray photoelectron spectroscopy. The measurements showed that the Ni 3+ state is reached after deposition whatever the deposition pressure but that an oxygen loss occurs during air annealing with a magnitude depending on the deposition pressure. X-ray diffraction measurements, fourpoint probe electrical measurements, and infrared optical properties vs temperature were consistent with these results. Thin films deposited at 0.5 Pa and annealed in air at 820 K lead to an orthorhombic structure which becomes rhombohedral when the deposition pressure reaches 7 Pa. The oxygen loss causes a deterioration of the electrical resistivity, which was also evidenced by the thermochromic behavior measured using Fourier transform infrared spectroscopy.

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Moderate pressure synthesis of rare earth nickelate with metal–insulator transition using polymeric precursors

Cited by 7 publications

References 26 publications

High pressure synthesis of SmNiO3 thin films and implications for thermodynamics of the nickelates

High pressure synthesis of SmNiO3 thin films and implications for thermodynamics of the nickelates

Synthesis and characterization of bulk Nd1−xSrxNiO2 and Nd
Wang
¹
,
Zheng
²
,
E.
³

et al. 2020
Phys. Rev. Materials
123
6
72
0
View full text Add to dashboard Cite

Mechanisms of Oxidation of NdNiO_3−δ Thermochromic Thin Films Synthesized by a Two-Step Method in Soft Conditions

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Moderate pressure synthesis of rare earth nickelate with metal–insulator transition using polymeric precursors

Cited by 7 publications

References 26 publications

High pressure synthesis of SmNiO3 thin films and implications for thermodynamics of the nickelates

High pressure synthesis of SmNiO3 thin films and implications for thermodynamics of the nickelates

Synthesis and characterization of bulk Nd1−xSrxNiO2 and NdWang1, Zheng2, E.3 et al. 2020Phys. Rev. Materials1236720View full textAdd to dashboardCite

Mechanisms of Oxidation of NdNiO3−δ Thermochromic Thin Films Synthesized by a Two-Step Method in Soft Conditions

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Product

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About

Synthesis and characterization of bulk Nd1−xSrxNiO2 and Nd
Wang
¹
,
Zheng
²
,
E.
³

et al. 2020
Phys. Rev. Materials
123
6
72
0
View full text Add to dashboard Cite

Mechanisms of Oxidation of NdNiO_3−δ Thermochromic Thin Films Synthesized by a Two-Step Method in Soft Conditions