Electrical properties of copper–manganese spinel solutions and their cation valence and cation distribution

Martin, Boris E.; Petric, Anthony

doi:10.1016/j.jpcs.2007.06.019

Cited by 47 publications

(31 citation statements)

References 23 publications

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“…It has been reported previously that incorporation of zinc can lead to the stabilization of the spinel phase against oxidation and phase transformation 38–40 . Incorporation of copper or cobalt reduces the resistivity of nickel manganite spinels by increasing the Mn 4+ ion concentration, which can lead to a larger number of sites for electron hopping 41–43 . It was found that cobalt‐doped nickel manganite films showed nearly spherical large particles incorporated into the growing film, which degraded the thickness uniformity, making these films unsuitable for device integration.…”

Section: Resultsmentioning

confidence: 99%

“…[38][39][40] Incorporation of copper or cobalt reduces the resistivity of nickel manganite spinels by increasing the Mn 41 ion concentration, which can lead to a larger number of sites for electron hopping. [41][42][43] It was found that cobalt-doped nickel manganite films showed nearly spherical large particles incorporated into the growing film, which degraded the thickness uniformity, making these films unsuitable for device integration. In contrast, zinc-doped nickel manganite films were significantly smoother and were found to be well crystallized without postdeposition annealing.…”

Section: Resultsmentioning

confidence: 99%

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Spin Spray‐Deposited Nickel Manganite Thermistor Films For Microbolometer Applications

Podraza

et al. 2010

Journal of the American Ceramic Society

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Nickel manganite thin films are good candidates for thermal imaging applications because of their large temperature coefficient of resistance (TCR), (>−3%/K) and good environmental stability. To enable low‐temperature deposition (90°C) on preexisting circuitry, a spin spray technique was developed for these materials. As‐deposited manganese oxide films show well‐developed X‐ray diffraction patterns, while as‐deposited nickel manganite films exhibit a nanocrystalline spinel structure. Low‐temperature (400°C) postdeposition annealing leads to densification of the nanocrystalline nickel manganite spinel films. Spectroscopic ellipsometry measurements on annealed films provide complex dielectric function spectra over a range from 0.75 to 5.15 eV with comparable features with those found in films prepared by a chemical solution method. Energy‐dispersive X‐ray spectroscopy indicates that the final composition of the films is Ni deficient relative to the starting solution composition. The TCR of the nickel manganite films annealed at 400°C in an argon atmosphere is −3.6%/K. Doping the nickel manganite films with zinc results in an improvement of crystallinity, but leads to substantial increases in the electrical resistivity. Copper doping reduces the resistivity of the films to <1.0 kΩ·cm without degrading the crystalline quality, thus resulting in films suitable for microbolometer applications.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Spin Spray‐Deposited Nickel Manganite Thermistor Films For Microbolometer Applications

Podraza

et al. 2010

Journal of the American Ceramic Society

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“…[ 442 ] Some other alkaline earth metal element free oxide materials were also tried with infi ltration method to prepare high-performance oxygen reduction electrodes. [443][444][445][446][447][448] With high electrical conductivity (≈190 S cm −1 ) and compatible TEC (12.2 × 10 −6 K −1 ) but low oxygen ionic conductivity, [ 443 ] the spinel Cu 1.25 Mn 1.75 O 4 phase was impregnated into an YSZ framework to form a new composite cathode, [ 444 ] and an infi ltration amount of 50 wt% was found to exhibit the lowest polarization resistance of 0.3 Ω cm 2 at 750 °C, which was much lower than 8.5 Ω cm 2 from a LSM infi ltrated YSZ cathode. In addition, the charge transfer process was likely to be the rate determining step at above 750 °C.…”

Section: Electrodes Infi Ltrated Into the Scaffold Of Electrolytesmentioning

confidence: 99%

Advances in Cathode Materials for Solid Oxide Fuel Cells: Complex Oxides without Alkaline Earth Metal Elements

Chen

Zhou

Ding

et al. 2015

Advanced Energy Materials

256

155

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Solid oxide fuel cells (SOFCs) represent one of the cleanest and most efficient options for the direct conversion of a wide variety of fuels to electricity. For example, SOFCs powered by natural gas are ideally suited for distributed power generation. However, the commercialization of SOFC technologies hinges on breakthroughs in materials development to dramatically reduce the cost while enhancing performance and durability. One of the critical obstacles to achieving high‐performance SOFC systems is the cathodes for oxygen reduction reaction (ORR), which perform poorly at low temperatures and degrade over time under operating conditions. Here a comprehensive review of the latest advances in the development of SOFC cathodes is presented: complex oxides without alkaline earth metal elements (because these elements could be vulnerable to phase segregation and contaminant poisoning). Various strategies are discussed for enhancing ORR activity while minimizing the effect of contaminant on electrode durability. Furthermore, some of the critical challenges are briefly highlighted and the prospects for future‐generation SOFC cathodes are discussed. A good understanding of the latest advances and remaining challenges in searching for highly active SOFC cathodes with robust tolerance to contaminants may provide useful guidance for the rational design of new materials and structures for commercially viable SOFC technologies.

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“…Cu x Mn 3-x O 4 spinel has high catalytic performance for steam reforming of methanol [7], and also exhibits high electrical conductivity (*200 S cm -1 at 800°C). Its catalytic activity for oxygen reduction is comparable to that of lanthanum manganese perovskite, stoichiometric CoFe 2 O 4 , and Co 2 MnO 4 spinel at intermediate temperature, which makes it a promising cathode material for solid oxide fuel cells [10]. Interesting physical and catalytic properties were expected in view of the presence of two Jahn-Teller ions in these materials, viz., Mn 3? and Cu 2?…”

Section: Introductionmentioning

confidence: 99%

In situ high-temperature X-ray and neutron diffraction of Cu–Mn oxide phases

et al. 2010

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Copper-manganese oxides were analyzed by in situ high-temperature powder neutron and X-ray diffraction to investigate their crystal structure. Cu-Mn spinel was found to form a continuous solid solution with cubic symmetry between Mn 3 O 4 and Cu 2 MnO 4 . A high-temperature phase with approximate composition Cu 5 Mn 4 O 9 was shown to have hexagonal symmetry. The cation distribution and lattice parameters of Cu-Mn spinel were resolved through Rietveld refinement of in situ neutron diffraction data. The results demonstrated that the Cu ion has a lower octahedral site preference than manganese ions, and quenching is not a reliable method to determine the equilibrium structure in the system.

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Electrical properties of copper–manganese spinel solutions and their cation valence and cation distribution

Cited by 47 publications

References 23 publications

Spin Spray‐Deposited Nickel Manganite Thermistor Films For Microbolometer Applications

Spin Spray‐Deposited Nickel Manganite Thermistor Films For Microbolometer Applications

Advances in Cathode Materials for Solid Oxide Fuel Cells: Complex Oxides without Alkaline Earth Metal Elements

In situ high-temperature X-ray and neutron diffraction of Cu–Mn oxide phases

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