GLORIA

GEOMAR Library Ocean Research Information Access

X

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Online Resource
    Online Resource
    Nanomagnetic properties of the meteorite cloudy zone
    Proceedings of the National Academy of Sciences ; 2018
    In:  Proceedings of the National Academy of Sciences Vol. 115, No. 49 ( 2018-12-04)
    Details
    In: Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 115, No. 49 ( 2018-12-04)
    Abstract: Meteorites contain a record of their thermal and magnetic history, written in the intergrowths of iron-rich and nickel-rich phases that formed during slow cooling. Of intense interest from a magnetic perspective is the “cloudy zone,” a nanoscale intergrowth containing tetrataenite—a naturally occurring hard ferromagnetic mineral that has potential applications as a sustainable alternative to rare-earth permanent magnets. Here we use a combination of high-resolution electron diffraction, electron tomography, atom probe tomography (APT), and micromagnetic simulations to reveal the 3D architecture of the cloudy zone with subnanometer spatial resolution and model the mechanism of remanence acquisition during slow cooling on the meteorite parent body. Isolated islands of tetrataenite are embedded in a matrix of an ordered superstructure. The islands are arranged in clusters of three crystallographic variants, which control how magnetic information is encoded into the nanostructure. The cloudy zone acquires paleomagnetic remanence via a sequence of magnetic domain state transformations (vortex to two domain to single domain), driven by Fe–Ni ordering at 320 °C. Rather than remanence being recorded at different times at different positions throughout the cloudy zone, each subregion of the cloudy zone records a coherent snapshot of the magnetic field that was present at 320 °C. Only the coarse and intermediate regions of the cloudy zone are found to be suitable for paleomagnetic applications. The fine regions, on the other hand, have properties similar to those of rare-earth permanent magnets, providing potential routes to synthetic tetrataenite-based magnetic materials.
    Type of Medium: Online Resource
    ISSN: 0027-8424 , 1091-6490
    URL: Article
    DOI: 10.1073/pnas.1809378115
    RVK:
    TA 1000
    RVK:
    WA 15000
    Language: English
    Publisher: Proceedings of the National Academy of Sciences
    Publication Date: 2018
    detail.hit.zdb_id: 209104-5
    detail.hit.zdb_id: 1461794-8
    SSG: 11
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 2
    Online Resource
    Online Resource
    Atom Probe Tomography Investigation of Clustering in Model P2O5-Doped Borosilicate Glasses for Nuclear Waste Vitrification
    Oxford University Press (OUP) ; 2024
    In:  Microscopy and Microanalysis ( 2024-07-08)
    Details
    In: Microscopy and Microanalysis, Oxford University Press (OUP), ( 2024-07-08)
    Abstract: Atom probe tomography (APT) has been utilized to investigate the microstructure of two model borosilicate glasses designed to understand the solubility limits of phosphorous pentoxide (P2O5). This component is found in certain high-level radioactive defence wastes destined for vitrification, where phase separation can potentially lead to a number of issues relating to the processing of the glass and its long-term chemical and structural stability. The development of suitable focused ion beam (FIB)-preparation routes and APT analysis conditions were initially determined for the model glasses, before examining their detailed microstructures. In a 3.0 mol% P2O5-doped glass, both visual inspection and sensitive statistical analysis of the APT data show homogeneous microstructures, while raising the content to 4.0 mol% initiates the formation of phosphorus-enriched nanoscale precipitates. This study confirms the expected inhomogeneities and phase separation of these glasses and offers routes to characterizing these at near-atomic scale resolution using APT.
    Type of Medium: Online Resource
    ISSN: 1431-9276 , 1435-8115
    URL: Article
    DOI: 10.1093/mam/ozae059
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2024
    detail.hit.zdb_id: 1481716-0
    SSG: 11
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 3
    Online Resource
    Online Resource
    Comparing the Consistency of Atom Probe Tomography Measurements of Small-Scale Segregation and Clustering Between the LEAP 3000 and LEAP 5000 Instruments
    Oxford University Press (OUP) ; 2017
    In:  Microscopy and Microanalysis Vol. 23, No. 2 ( 2017-04), p. 227-237
    Details
    In: Microscopy and Microanalysis, Oxford University Press (OUP), Vol. 23, No. 2 ( 2017-04), p. 227-237
    Abstract: The local electrode atom probe (LEAP) has become the primary instrument used for atom probe tomography measurements. Recent advances in detector and laser design, together with updated hit detection algorithms, have been incorporated into the latest LEAP 5000 instrument, but the implications of these changes on measurements, particularly the size and chemistry of small clusters and elemental segregations, have not been explored. In this study, we compare data sets from a variety of materials with small-scale chemical heterogeneity using both a LEAP 3000 instrument with 37% detector efficiency and a 532-nm green laser and a new LEAP 5000 instrument with a manufacturer estimated increase to 52% detector efficiency, and a 355-nm ultraviolet laser. In general, it was found that the number of atoms within small clusters or surface segregation increased in the LEAP 5000, as would be expected by the reported increase in detector efficiency from the LEAP 3000 architecture, but subtle differences in chemistry were observed which are attributed to changes in the way multiple hit detection is calculated using the LEAP 5000.
    Type of Medium: Online Resource
    ISSN: 1431-9276 , 1435-8115
    URL: Article
    DOI: 10.1017/S1431927617000356
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2017
    detail.hit.zdb_id: 1481716-0
    SSG: 11
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 4
    Online Resource
    Online Resource
    The microstructure of non-polar a-plane (112¯0) InGaN quantum wells
    AIP Publishing ; 2016
    In:  Journal of Applied Physics Vol. 119, No. 17 ( 2016-05-07)
    Details
    In: Journal of Applied Physics, AIP Publishing, Vol. 119, No. 17 ( 2016-05-07)
    Abstract: Atom probe tomography and quantitative scanning transmission electron microscopy are used to assess the composition of non-polar a-plane (11-20) InGaN quantum wells for applications in optoelectronics. The average quantum well composition measured by atom probe tomography and quantitative scanning transmission electron microscopy quantitatively agrees with measurements by X-ray diffraction. Atom probe tomography is further applied to study the distribution of indium atoms in non-polar a-plane (11-20) InGaN quantum wells. An inhomogeneous indium distribution is observed by frequency distribution analysis of the atom probe tomography measurements. The optical properties of non-polar (11-20) InGaN quantum wells with indium compositions varying from 7.9% to 20.6% are studied. In contrast to non-polar m-plane (1-100) InGaN quantum wells, the non-polar a-plane (11-20) InGaN quantum wells emit at longer emission wavelengths at the equivalent indium composition. The non-polar a-plane (11-20) quantum wells also show broader spectral linewidths. The longer emission wavelengths and broader spectral linewidths may be related to the observed inhomogeneous indium distribution.
    Type of Medium: Online Resource
    ISSN: 0021-8979 , 1089-7550
    URL: Article
    DOI: 10.1063/1.4948299
    Language: English
    Publisher: AIP Publishing
    Publication Date: 2016
    detail.hit.zdb_id: 220641-9
    detail.hit.zdb_id: 3112-4
    detail.hit.zdb_id: 1476463-5
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 5
    Online Resource
    Online Resource
    Structural and compositional analysis of (InGa)(AsSb)/GaAs/GaP Stranski–Krastanov quantum dots
    Springer Science and Business Media LLC ; 2021
    In:  Light: Science & Applications Vol. 10, No. 1 ( 2021-06-15)
    Details
    In: Light: Science & Applications, Springer Science and Business Media LLC, Vol. 10, No. 1 ( 2021-06-15)
    Abstract: We investigated metal-organic vapor phase epitaxy grown (InGa)(AsSb)/GaAs/GaP Stranski–Krastanov quantum dots (QDs) with potential applications in QD-Flash memories by cross-sectional scanning tunneling microscopy (X-STM) and atom probe tomography (APT). The combination of X-STM and APT is a very powerful approach to study semiconductor heterostructures with atomic resolution, which provides detailed structural and compositional information on the system. The rather small QDs are found to be of truncated pyramid shape with a very small top facet and occur in our sample with a very high density of ∼4 × 10 11  cm −2 . APT experiments revealed that the QDs are GaAs rich with smaller amounts of In and Sb. Finite element (FE) simulations are performed using structural data from X-STM to calculate the lattice constant and the outward relaxation of the cleaved surface. The composition of the QDs is estimated by combining the results from X-STM and the FE simulations, yielding ∼In x Ga 1 −  x As 1 −  y Sb y , where x  = 0.25–0.30 and y  = 0.10–0.15. Noticeably, the reported composition is in good agreement with the experimental results obtained by APT, previous optical, electrical, and theoretical analysis carried out on this material system. This confirms that the InGaSb and GaAs layers involved in the QD formation have strongly intermixed. A detailed analysis of the QD capping layer shows the segregation of Sb and In from the QD layer, where both APT and X-STM show that the Sb mainly resides outside the QDs proving that Sb has mainly acted as a surfactant during the dot formation. Our structural and compositional analysis provides a valuable insight into this novel QD system and a path for further growth optimization to improve the storage time of the QD-Flash memory devices.
    Type of Medium: Online Resource
    ISSN: 2047-7538
    URL: Article
    DOI: 10.1038/s41377-021-00564-z
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2021
    detail.hit.zdb_id: 2662628-7
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 6
    Online Resource
    Online Resource
    The Kinetics of Primary Alpha Plate Growth in Titanium Alloys
    Springer Science and Business Media LLC ; 2020
    In:  Metallurgical and Materials Transactions A Vol. 51, No. 1 ( 2020-01), p. 131-141
    Details
    In: Metallurgical and Materials Transactions A, Springer Science and Business Media LLC, Vol. 51, No. 1 ( 2020-01), p. 131-141
    Abstract: The kinetics of primary α -Ti colony/Widmanstätten plate growth from the β are examined in Ti-6246, comparing a simple quasi-analytic model to experiment. The plate growth velocity depends sensitively both on the diffusivity D ( T ) of the rate-limiting species and on the supersaturation around the growing plate. These result in a maxima in growth velocity around 40 K below the transus, once sufficient supersaturation is available to drive the plate growth. In Ti-6246, the plate growth velocity was found to be around 0.32 μ m min −1 at 850 °C, which was in good agreement with the model prediction of 0.36 μ m min −1 . The solute field around the growing plates, and the plate thickness, was found to be quite variable, due to the intergrowth of plates and soft impingement. This solute field was found to extend to up to 30 nm, and the interface concentration in the β was found to be around 6.4 at. pct Mo. It was found that the increasing O content from 500 to 1500 wppm will have minimal effect on the plate lengths expected during continuous cooling; in contrast, Mo approximately doubles the plate lengths obtained for every 2 wt pct Mo reduction. Alloys using V as the β stabilizer instead of Mo are expected to have much faster plate growth kinetics at nominally equivalent V contents. These findings will provide a useful tool for the integrated design of alloys and process routes to achieve tailored microstructures.
    Type of Medium: Online Resource
    ISSN: 1073-5623 , 1543-1940
    URL: Article
    DOI: 10.1007/s11661-019-05472-x
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2020
    detail.hit.zdb_id: 1179415-X
    detail.hit.zdb_id: 2037517-7
    detail.hit.zdb_id: 192156-3
    SSG: 19,1
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 7
    Online Resource
    Online Resource
    Indium clustering in a -plane InGaN quantum wells as evidenced by atom probe tomography
    AIP Publishing ; 2015
    In:  Applied Physics Letters Vol. 106, No. 7 ( 2015-02-16)
    Details
    In: Applied Physics Letters, AIP Publishing, Vol. 106, No. 7 ( 2015-02-16)
    Abstract: Atom probe tomography (APT) has been used to characterize the distribution of In atoms within non-polar a-plane InGaN quantum wells (QWs) grown on a GaN pseudo-substrate produced using epitaxial lateral overgrowth. Application of the focused ion beam microscope enabled APT needles to be prepared from the low defect density regions of the grown sample. A complementary analysis was also undertaken on QWs having comparable In contents grown on polar c-plane sample pseudo-substrates. Both frequency distribution and modified nearest neighbor analyses indicate a statistically non-randomized In distribution in the a-plane QWs, but a random distribution in the c-plane QWs. This work not only provides insights into the structure of non-polar a-plane QWs but also shows that APT is capable of detecting as-grown nanoscale clustering in InGaN and thus validates the reliability of earlier APT analyses of the In distribution in c-plane InGaN QWs which show no such clustering.
    Type of Medium: Online Resource
    ISSN: 0003-6951 , 1077-3118
    URL: Article
    DOI: 10.1063/1.4909514
    RVK:
    UA 1000
    Language: English
    Publisher: AIP Publishing
    Publication Date: 2015
    detail.hit.zdb_id: 211245-0
    detail.hit.zdb_id: 1469436-0
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 8
    Online Resource
    Online Resource
    Radiation-induced segregation in W-Re: from kinetic Monte Carlo simulations to atom probe tomography experiments
    Springer Science and Business Media LLC ; 2019
    In:  The European Physical Journal B Vol. 92, No. 10 ( 2019-10)
    Details
    In: The European Physical Journal B, Springer Science and Business Media LLC, Vol. 92, No. 10 ( 2019-10)
    Abstract: A viable fusion power station is reliant on the development of plasma facing materials that can withstand the combined effects of high temperature operation and high neutron doses. In this study we focus on W, the most promising candidate material. Re is the primary transmutation product and has been shown to induce embrittlement through cluster formation and precipitation below its predicted solubility limit in W. We investigate the mechanism behind this using a kinetic Monte Carlo model, implemented into Stochastic Parallel PARticle Kinetic Simulator (SPPARKS) code and parameterised with a pairwise energy model for both interstitial and vacancy type defects. By introducing point defect sinks into our simulation cell, we observe the formation of Re rich clusters which have a concentration similar to that observed in ion irradiation experiments. We also compliment our computational work with atom probe tomography (APT) of ion implanted, model W-Re alloys. The segregation of Re to grain boundaries is observed in both our APT and KMC simulations. Graphical abstract
    Type of Medium: Online Resource
    ISSN: 1434-6028 , 1434-6036
    URL: Article
    DOI: 10.1140/epjb/e2019-100244-y
    RVK:
    UA 3858.B
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2019
    detail.hit.zdb_id: 1459068-2
    detail.hit.zdb_id: 1397768-4
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 9
    Online Resource
    Online Resource
    Developing Atom Probe Tomography of Phyllosilicates in Preparation for Extra‐Terrestrial Sample Return
    Wiley ; 2021
    In:  Geostandards and Geoanalytical Research Vol. 45, No. 3 ( 2021-09), p. 427-441
    Details
    In: Geostandards and Geoanalytical Research, Wiley, Vol. 45, No. 3 ( 2021-09), p. 427-441
    Abstract: Hydrous phyllosilicate minerals, including the serpentine subgroup, are likely to be major constituents of material that will be bought back to Earth by missions to Mars and to primitive asteroids Ryugu and Bennu. Small quantities ( 〈  60 g) of micrometre‐sized, internally heterogeneous material will be available for study, requiring minimally destructive techniques. Many conventional methods are unsuitable for phyllosilicates as they are typically finely crystalline and electron beam‐sensitive resulting in amorphisation and dehydration. New tools will be required for nanoscale characterisation of these precious extra‐terrestrial samples. Here we test the effectiveness of atom probe tomography (APT) for this purpose. Using lizardite from the Ronda peridotite, Spain, as a terrestrial analogue, we outline an effective analytical protocol to extract nanoscale chemical and structural measurements of phyllosilicates. The potential of APT is demonstrated by the unexpected finding that the Ronda lizardite contains SiO‐rich nanophases, consistent with opaline silica that formed as a by‐product of the serpentinisation of olivine. Our new APT approach unlocks previously unobservable nanominerals and nanostructures within phyllosilicates owing to resolution limitations of more established imaging techniques. APT will provide unique insights into the processes and products of water/rock interaction on Earth, Mars and primitive asteroids.
    Type of Medium: Online Resource
    ISSN: 1639-4488 , 1751-908X
    URL: Issue
    URL: Article
    DOI: 10.1111/ggr.v45.3
    DOI: 10.1111/ggr.12382
    Language: English
    Publisher: Wiley
    Publication Date: 2021
    detail.hit.zdb_id: 2276474-4
    detail.hit.zdb_id: 2595219-5
    detail.hit.zdb_id: 2134777-3
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 10
    Online Resource
    Online Resource
    Nanoscale Stoichiometric Analysis of a High-Temperature Superconductor by Atom Probe Tomography
    Oxford University Press (OUP) ; 2017
    In:  Microscopy and Microanalysis Vol. 23, No. 2 ( 2017-04), p. 414-424
    Details
    In: Microscopy and Microanalysis, Oxford University Press (OUP), Vol. 23, No. 2 ( 2017-04), p. 414-424
    Abstract: The functional properties of the high-temperature superconductor Y 1 Ba 2 Cu 3 O 7− δ (Y-123) are closely correlated to the exact stoichiometry and oxygen content. Exceeding the critical value of 1 oxygen vacancy for every five unit cells ( δ 〉 0.2, which translates to a 1.5 at% deviation from the nominal oxygen stoichiometry of Y 7.7 Ba 15.3 Cu 23 O 54− δ ) is sufficient to alter the superconducting properties. Stoichiometry at the nanometer scale, particularly of oxygen and other lighter elements, is extremely difficult to quantify in complex functional ceramics by most currently available analytical techniques. The present study is an analysis and optimization of the experimental conditions required to quantify the local nanoscale stoichiometry of single crystal yttrium barium copper oxide (YBCO) samples in three dimensions by atom probe tomography (APT). APT analysis required systematic exploration of a wide range of data acquisition and processing conditions to calibrate the measurements. Laser pulse energy, ion identification, and the choice of range widths were all found to influence composition measurements. The final composition obtained from melt-grown crystals with optimized superconducting properties was Y 7.9 Ba 10.4 Cu 24.4 O 57.2 .
    Type of Medium: Online Resource
    ISSN: 1431-9276 , 1435-8115
    URL: Article
    DOI: 10.1017/S1431927616012757
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2017
    detail.hit.zdb_id: 1481716-0
    SSG: 11
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...