The Experts below are selected from a list of 6594 Experts worldwide ranked by ideXlab platform

Cristina Messa - One of the best experts on this subject based on the ideXlab platform.

Michalis Charilaou - One of the best experts on this subject based on the ideXlab platform.

  • unconventional magnetization textures and domain wall pinning in sm co magnets
    Scientific Reports, 2020
    Co-Authors: Leonardo Pierobon, Rafal E Duninborkowski, Andras Kovacs, R Schaublin, Stephan S A Gerstl, Jan Caron, Urs V Wyss, Jorg F Loffler, Michalis Charilaou
    Abstract:

    Some of the best-performing high-temperature magnets are Sm–Co-based alloys with a microstructure that comprises an $$\hbox {Sm}_2\hbox {Co}_{17}$$ matrix and magnetically hard $$\hbox {SmCo}_5$$ cell walls. This generates a dense domain-wall-pinning network that endows the material with remarkable magnetic hardness. A precise understanding of the coupling between magnetism and microstructure is essential for enhancing the performance of Sm–Co magnets, but experiments and theory have not yet converged to a unified model. Here, transmission electron microscopy, atom probe tomography, and nanometer-resolution off-axis electron holography have been combined with micromagnetic simulations to reveal that the magnetization state in Sm–Co magnets results from curling instabilities and domain-wall pinning effects at the intersections of phases with different magnetic hardness. Additionally, this study has found that topologically non-trivial magnetic domains separated by a complex network of domain walls play a key role in the magnetic state by acting as nucleation sites for magnetization reversal. These findings reveal previously hidden aspects of magnetism in Sm–Co magnets and, by identifying weak points in the microstructure, provide guidelines for improving these high-performance magnetic materials.

  • unconventional magnetization textures and domain wall pinning in sm co magnets
    arXiv: Materials Science, 2019
    Co-Authors: Leonardo Pierobon, Rafal E Duninborkowski, Andras Kovacs, R Schaublin, Stephan S A Gerstl, Jan Caron, Urs V Wyss, Jorg F Loffler, Michalis Charilaou
    Abstract:

    The most powerful magnets for high temperature applications are Sm-Co-based alloys with a microstructure that combines magnetically soft and hard regions. The microstructure consists of a dense domain-wall-pinning network that endows the material with remarkable magnetic hardness. A precise understanding of the coupling between magnetism and microstructure is essential for enhancing the performance of Sm-Co magnets, but experiments and theory have not yet converged to a unified model. Here, we combine transmission electron microscopy, atom probe tomography, and nanometer-resolution off-axis electron holography with micromagnetic simulations to show that the magnetization processes in Sm-Co magnets result from an interplay between curling instabilities and pinning effects at the intersections between magnetically soft and hard regions. We also find that topologically non-trivial magnetic domains separated by a complex network of domain walls play a key role in the magnetic state. Our findings reveal a previously hidden aspect of magnetism and provide insight into the full potential of high-performance magnetic materials.

Fabio Manferrari - One of the best experts on this subject based on the ideXlab platform.

  • how does 68 ga prostate specific membrane antigen positron emission tomography computed tomography impact the management of patients with prostate cancer recurrence after surgery
    International Journal of Urology, 2019
    Co-Authors: Lorenzo Bianchi, Riccardo Schiavina, Marco Borghesi, Francesco Ceci, A Angiolini, F Chessa, M Droghetti, Alessandro Bertaccini, Fabio Manferrari
    Abstract:

    Objective To evaluate the clinical impact of 68 Ga-prostate-specific membrane antigen positron emission tomography/computed tomography on the planned management of prostate cancer patients with biochemical recurrence after surgery. Methods We enrolled 276 prostate cancer patients referred to 68 Ga-prostate-specific membrane antigen positron emission tomography/computed tomography due to biochemical recurrence after surgery (two consecutive prostate-specific antigen assays ≥0.2 ng/mL). First, the detection rate of 68 Ga-prostate-specific membrane antigen positron emission tomography/computed tomography was assessed according to different prostate-specific antigen levels. Second, the independent predictors of 68 Ga-prostate-specific membrane antigen positron emission tomography/computed tomography positive results were assessed. Finally, the intended treatment before revision of 68 Ga-prostate-specific membrane antigen positron emission tomography/computed tomography was assessed by a multidisciplinary team based on the European Association of Urology guidelines, patient clinical condition and clinical parameters. Then, re-assessment of the treatment plan was prospectively recorded by the same board after revision of 68 Ga-prostate-specific membrane antigen positron emission tomography/computed tomography. The effective clinical impact of 68 Ga-prostate-specific membrane antigen positron emission tomography/computed tomography was rated as major (change in therapeutic approach), minor (same treatment, but modified therapeutic strategy) or none. Results The overall detection rate of 68 Ga-prostate-specific membrane antigen positron emission tomography/computed tomography was 47.5%. Prostate-specific antigen at 68 Ga-prostate-specific membrane antigen positron emission tomography/computed tomography (odds ratio 3.52) and prostate-specific antigen doubling time 2 ng/mL, respectively. Conclusions 68 Ga-prostate-specific membrane antigen positron emission tomography/computed tomography allows clinicians to radically change the intended treatment approach before imaging evaluation, in roughly two out three individuals.

  • 11c choline positron emission tomography computerized tomography for tumor localization of primary prostate cancer in comparison with 12 core biopsy
    The Journal of Urology, 2006
    Co-Authors: Giuseppe Martorana, Riccardo Schiavina, Alessandro Bertaccini, Fabio Manferrari, Barbara Corti, Mohsen Farsad, Eugenio Salizzoni, Eugenio Brunocilla, Paolo Castellucci, Stefano Fanti
    Abstract:

    Purpose: 11C-choline positron emission tomography is an innovative imaging technique for prostate cancer. We assessed the sensitivity of positron emission tomography used together with computerized tomography for intraprostatic localization of primary prostate cancer on a nodule-by-nodule basis, and compared its performance with 12-core transrectal biopsy.Materials and Methods: In 43 patients with known prostate cancer who had received positron emission tomography/computerized tomography before initial biopsy, we assessed sensitivity of positron emission tomography/computerized tomography for localization of nodules 5 mm or greater (those theoretically large enough for visualization) using radical prostatectomy histopathology as the reference standard. Comparison with transrectal ultrasound guided biopsy was based on sextant assessment of all cancer foci following sextant-by-sextant matching and reconstruction. Sensitivity/specificity of positron emission tomography/computerized tomography and magnetic re...

Rafal E Duninborkowski - One of the best experts on this subject based on the ideXlab platform.

  • unconventional magnetization textures and domain wall pinning in sm co magnets
    Scientific Reports, 2020
    Co-Authors: Leonardo Pierobon, Rafal E Duninborkowski, Andras Kovacs, R Schaublin, Stephan S A Gerstl, Jan Caron, Urs V Wyss, Jorg F Loffler, Michalis Charilaou
    Abstract:

    Some of the best-performing high-temperature magnets are Sm–Co-based alloys with a microstructure that comprises an $$\hbox {Sm}_2\hbox {Co}_{17}$$ matrix and magnetically hard $$\hbox {SmCo}_5$$ cell walls. This generates a dense domain-wall-pinning network that endows the material with remarkable magnetic hardness. A precise understanding of the coupling between magnetism and microstructure is essential for enhancing the performance of Sm–Co magnets, but experiments and theory have not yet converged to a unified model. Here, transmission electron microscopy, atom probe tomography, and nanometer-resolution off-axis electron holography have been combined with micromagnetic simulations to reveal that the magnetization state in Sm–Co magnets results from curling instabilities and domain-wall pinning effects at the intersections of phases with different magnetic hardness. Additionally, this study has found that topologically non-trivial magnetic domains separated by a complex network of domain walls play a key role in the magnetic state by acting as nucleation sites for magnetization reversal. These findings reveal previously hidden aspects of magnetism in Sm–Co magnets and, by identifying weak points in the microstructure, provide guidelines for improving these high-performance magnetic materials.

  • unconventional magnetization textures and domain wall pinning in sm co magnets
    arXiv: Materials Science, 2019
    Co-Authors: Leonardo Pierobon, Rafal E Duninborkowski, Andras Kovacs, R Schaublin, Stephan S A Gerstl, Jan Caron, Urs V Wyss, Jorg F Loffler, Michalis Charilaou
    Abstract:

    The most powerful magnets for high temperature applications are Sm-Co-based alloys with a microstructure that combines magnetically soft and hard regions. The microstructure consists of a dense domain-wall-pinning network that endows the material with remarkable magnetic hardness. A precise understanding of the coupling between magnetism and microstructure is essential for enhancing the performance of Sm-Co magnets, but experiments and theory have not yet converged to a unified model. Here, we combine transmission electron microscopy, atom probe tomography, and nanometer-resolution off-axis electron holography with micromagnetic simulations to show that the magnetization processes in Sm-Co magnets result from an interplay between curling instabilities and pinning effects at the intersections between magnetically soft and hard regions. We also find that topologically non-trivial magnetic domains separated by a complex network of domain walls play a key role in the magnetic state. Our findings reveal a previously hidden aspect of magnetism and provide insight into the full potential of high-performance magnetic materials.

  • interferometric methods for mapping static electric and magnetic fields
    Comptes Rendus Physique, 2014
    Co-Authors: Giulio Pozzi, Takeshi Kasama, Marco Beleggia, Rafal E Duninborkowski
    Abstract:

    Abstract The mapping of static electric and magnetic fields using electron probes with a resolution and sensitivity that are sufficient to reveal nanoscale features in materials requires the use of phase-sensitive methods such as the shadow technique, coherent Foucault imaging and the Transport of Intensity Equation. Among these approaches, image-plane off-axis electron holography in the transmission electron microscope has acquired a prominent role thanks to its quantitative capabilities and broad range of applicability. After a brief overview of the main ideas and methods behind field mapping, we focus on theoretical models that form the basis of the quantitative interpretation of electron holographic data. We review the application of electron holography to a variety of samples (including electric fields associated with p–n junctions in semiconductors, quantized magnetic flux in superconductors and magnetization topographies in nanoparticles and other magnetic materials) and electron-optical geometries (including multiple biprism, amplitude and mixed-type set-ups). We conclude by highlighting the emerging perspectives of (i) three-dimensional field mapping using electron holographic tomography and (ii) the model-independent determination of the locations and magnitudes of field sources (electric charges and magnetic dipoles) directly from electron holographic data.

  • electron tomography and holography in materials science
    Nature Materials, 2009
    Co-Authors: Paul A Midgley, Rafal E Duninborkowski
    Abstract:

    The rapid development of electron tomography, in particular the introduction of novel tomographic imaging modes, has led to the visualization and analysis of three-dimensional structural and chemical information from materials at the nanometre level. In addition, the phase information revealed in electron holograms allows electrostatic and magnetic potentials to be mapped quantitatively with high spatial resolution and, when combined with tomography, in three dimensions. Here we present an overview of the techniques of electron tomography and electron holography and demonstrate their capabilities with the aid of case studies that span materials science and the interface between the physical sciences and the life sciences.

  • three dimensional electrostatic potential of a si p n junction revealed using tomographic electron holography
    Journal of Physics: Conference Series, 2006
    Co-Authors: A C Twitchett, Rafal E Duninborkowski, T J V Yates, S B Newcomb, Paul A Midgley
    Abstract:

    Off-axis electron holography and tomography have been combined to examine the 3-D electrostatic potential associated with a thin specimen containing a Si p-n junction. The device was prepared in a novel specimen geometry using focused ion beam milling, and a series of holograms was acquired over a tilt range of -70° to 70°. Simultaneous iterative reconstruction was used to reconstruct the 3-D electrostatic potential in the specimen. The experimental results were compared with simulations of the potential variation. Quantitative results from the central, 'bulk' semiconducting regions and from the surface layers were extracted from the 3-D reconstruction.

Stefano Fanti - One of the best experts on this subject based on the ideXlab platform.

  • 11c choline positron emission tomography computerized tomography for tumor localization of primary prostate cancer in comparison with 12 core biopsy
    The Journal of Urology, 2006
    Co-Authors: Giuseppe Martorana, Riccardo Schiavina, Alessandro Bertaccini, Fabio Manferrari, Barbara Corti, Mohsen Farsad, Eugenio Salizzoni, Eugenio Brunocilla, Paolo Castellucci, Stefano Fanti
    Abstract:

    Purpose: 11C-choline positron emission tomography is an innovative imaging technique for prostate cancer. We assessed the sensitivity of positron emission tomography used together with computerized tomography for intraprostatic localization of primary prostate cancer on a nodule-by-nodule basis, and compared its performance with 12-core transrectal biopsy.Materials and Methods: In 43 patients with known prostate cancer who had received positron emission tomography/computerized tomography before initial biopsy, we assessed sensitivity of positron emission tomography/computerized tomography for localization of nodules 5 mm or greater (those theoretically large enough for visualization) using radical prostatectomy histopathology as the reference standard. Comparison with transrectal ultrasound guided biopsy was based on sextant assessment of all cancer foci following sextant-by-sextant matching and reconstruction. Sensitivity/specificity of positron emission tomography/computerized tomography and magnetic re...