Mapping grain boundary heterogeneity at the nanoscale in a positive temperature coefficient of resistivity ceramic

Holsgrove, Kristina; Kepaptsoglou, Demie; Douglas, Alan; Ramasse, Quentin M.; Prestat, Éric; Haigh, Sarah J.; Ward, Michael B.; Kumar, Amit; Gregg, J. M.; Arredondo, Miryam

doi:10.1063/1.4989396

Cited by 13 publications

(13 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This flattening of the peaks has been previously reported in multiferroic thin films containing (i) interfacial cation intermixing , and (ii) dislocations, yet a conclusion on the physical origin of this effect is still elusive. In both cases, it is generally accepted that this feature originates from the presence of oxygen vacancies .…”

Section: Resultsmentioning

confidence: 83%

“…In both cases, it is generally accepted that this feature originates from the presence of oxygen vacancies. 23 However, this is not a general consensus as several studies have also reported such flattening of the O K-edge in samples where no oxygen vacancies are suspected to exist 72 and others have suggested interfacial cation intermixing as the possible origin for this feature. 74 Probe channeling effects may also play a role in smoothing out the spectral features.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Effects of Multiple Local Environments on Electron Energy Loss Spectra of Epitaxial Perovskite Interfaces

et al. 2022

Self Cite

View full text Add to dashboard Cite

The role of local chemical environments in the electron energy loss spectra of complex multiferroic oxides was studied using computational and experimental techniques. The evolution of the O K-edge across an interface between bismuth ferrite (BFO) and lanthanum strontium manganate (LSMO) was considered through spectral averaging over crystallographically equivalent positions to capture the periodicity of the local O environments. Computational techniques were used to investigate the contribution of individual atomic environments to the overall spectrum, and the role of doping and strain was considered. Chemical variation, even at the low level, was found to have a major impact on the spectral features, whereas strain only induced a small chemical shift to the edge onset energy. Through a combination of these methods, it was possible to explain experimentally observed effects such as spectral flattening near the interface as the combination of spectral responses from multiple local atomic environments.

show abstract

Section: Resultsmentioning

confidence: 83%

Section: Resultsmentioning

confidence: 99%

Effects of Multiple Local Environments on Electron Energy Loss Spectra of Epitaxial Perovskite Interfaces

et al. 2022

Self Cite

View full text Add to dashboard Cite

show abstract

“…Our work demonstrates the benefit of quantitative atomic‐scale measurements at polar grain boundaries, providing additional opportunities for the study of emergent local electronic phenomena and the complex influence of phase relations, reaction kinetics, and sintering temperature for the electronic properties of grain boundaries. A possible field of application is the detection and quantification of oxygen defects and compositional inhomogeneities at grain boundaries, which are believed to play an important role for the physical properties of various polar materials, including ceramics based on BiFeO 3 , [ 44 ] BaTiO 3 , [ 45 ] and HfZrO 2 [ 46 ] . Furthermore, our results show additional opportunities for the property engineering of polar quasi‐2D systems, applicable to ferroelectric oxides and nonmetallic inorganics in general.…”

Section: Discussionmentioning

confidence: 99%

Quantitative Mapping of Chemical Defects at Charged Grain Boundaries in a Ferroelectric Oxide

Hunnestad

Schultheiß

et al. 2023

Advanced Materials

View full text Add to dashboard Cite

Polar discontinuities, as well as compositional and structural changes at oxide interfaces can give rise to a large variety of electronic and ionic phenomena. In contrast to earlier work focused on domain walls and epitaxial systems, this work investigates the relation between polar discontinuities and the local chemistry at grain boundaries in polycrystalline ferroelectric ErMnO3. Using orientation mapping and scanning probe microscopy (SPM) techniques, the polycrystalline material is demonstrated to develop charged grain boundaries with enhanced electronic conductance. By performing atom probe tomography (APT) measurements, an enrichment of erbium and a depletion of oxygen at all grain boundaries are found. The observed compositional changes translate into a charge that exceeds possible polarization‐driven effects, demonstrating that structural phenomena rather than electrostatics determine the local chemical composition and related changes in the electronic transport behavior. The study shows that the charged grain boundaries behave distinctly different from charged domain walls, giving additional opportunities for property engineering at polar oxide interfaces.

show abstract

“…As the temperature exceeds the Curie temperature of the PTC ceramic material, ϕ 0 increases based on Equation (6). According to Equation (5), ρ shows the positive temperature effect of electrical resistivity [27]. The positive electrical resistivity-temperature properties of PTC materials are complementary to the negative electrical resistivity-temperature properties of polymeric materials.…”

Section: Mechanism To the Suppressed Negative Temperature Coefficient...mentioning

confidence: 99%

Electrical resistivity‐temperature characteristics enhancement of insulating cross‐linked polyethylene composites by incorporating positive temperature coefficient particles with different Curie temperatures

et al. 2022

View full text Add to dashboard Cite

Incorporating positive temperature coefficient (PTC) ceramic particles into polymers provides a prospective alternative solution for suppressing severe electric field distortions caused by negative temperature coefficient (NTC) of electrical resistivity within polymer insulation in high voltage direct current cable. The effect of the Curie temperature of PTC particles on the inhibition of the NTC effect of cross-linked polyethylene (XLPE) is investigated in this study. Positive temperature coefficient particles with varied Curie temperatures are surface-modified and melt blending with XLPE. The modified particles are dispersed on averagely in the matrix. The electrical resistivity, space charge behaviour, and direct current (DC) electrical breakdown strength of the samples are investigated at different temperatures, exploring the effect of the Curie temperature of PTC particles on suppressing the NTC effect of XLPE. It is demonstrated that the reduction in Curie temperature can further suppress the NTC effect of XLPE, enhance the DC strength at elevated temperatures, and inhibit the internal space charge accumulation. The reduction in the Curie temperatures means that the initiation of the PTC effect advances, exhibiting a higher potential barrier and inhibiting the NTC effect more effectively. This work may give a reference for improving the temperature stability of DC properties for XLPE cable insulation.

show abstract

Mapping grain boundary heterogeneity at the nanoscale in a positive temperature coefficient of resistivity ceramic

Cited by 13 publications

References 40 publications

Effects of Multiple Local Environments on Electron Energy Loss Spectra of Epitaxial Perovskite Interfaces

Effects of Multiple Local Environments on Electron Energy Loss Spectra of Epitaxial Perovskite Interfaces

Quantitative Mapping of Chemical Defects at Charged Grain Boundaries in a Ferroelectric Oxide

Electrical resistivity‐temperature characteristics enhancement of insulating cross‐linked polyethylene composites by incorporating positive temperature coefficient particles with different Curie temperatures

Contact Info

Product

Resources

About