| 1. |
- Bommanaboyena, S. P., et al.
(författare)
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Readout of an antiferromagnetic spintronics system by strong exchange coupling of Mn2Au and Permalloy
- 2021
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- In antiferromagnetic spintronics, the read-out of the staggered magnetization or Néel vector is the key obstacle to harnessing the ultra-fast dynamics and stability of antiferromagnets for novel devices. Here, we demonstrate strong exchange coupling of Mn2Au, a unique metallic antiferromagnet that exhibits Néel spin-orbit torques, with thin ferromagnetic Permalloy layers. This allows us to benefit from the well-established read-out methods of ferromagnets, while the essential advantages of antiferromagnetic spintronics are only slightly diminished. We show one-to-one imprinting of the antiferromagnetic on the ferromagnetic domain pattern. Conversely, alignment of the Permalloy magnetization reorients the Mn2Au Néel vector, an effect, which can be restricted to large magnetic fields by tuning the ferromagnetic layer thickness. To understand the origin of the strong coupling, we carry out high resolution electron microscopy imaging and we find that our growth yields an interface with a well-defined morphology that leads to the strong exchange coupling.
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| 2. |
- Salazar-Alvarez, German, et al.
(författare)
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Direct evidence of imprinted vortex states in the antiferromagnet of exchange biased microdisks
- 2009
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 95:1, s. 012510-
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Tidskriftsartikel (refereegranskat)abstract
- The magnetic domain structure of patterned antiferromagnetic/ferromagnetic Ir20Mn80/Ni80Fe20 bilayer microdisk arrays has been investigated using layer-specific polarized x-ray photoemission electron microscopy and magnetic circular dichroism. Magnetic imaging at the Fe and Mn L-edge resonances provided direct evidence of a vortex state imprinted into the antiferromagnet at the interface. The opposite magnetic contrast between the layers indicated a reversed chirality of the imprinted vortex state, and a quantitative analysis of the magnetic moment from the dichroism spectra showed that uncompensated Mn spins equivalent to about 60% of a monolayer of bulk Ir20Mn80 contributed to the imprinted information at the interface.
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| 3. |
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| 4. |
- Fitzer, Susan C., et al.
(författare)
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Biomineral shell formation under ocean acidification : a shift from order to chaos
- 2016
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- Biomineral production in marine organisms employs transient phases of amorphous calcium carbonate (ACC) in the construction of crystalline shells. Increasing seawater pCO(2) leads to ocean acidification (OA) with a reduction in oceanic carbonate concentration which could have a negative impact on shell formation and therefore survival. We demonstrate significant changes in the hydrated and dehydrated forms of ACC in the aragonite and calcite layers of Mytilus edulis shells cultured under acidification conditions (1000 mu atm pCO(2)) compared to present day conditions (380 mu atm pCO(2)). In OA conditions, Mytilus edulis has more ACC at crystalisation sites. Here, we use the high-spatial resolution of synchrotron X-ray Photo Emission Electron Microscopy (XPEEM) combined with X-ray Absorption Spectroscopy (XAS) to investigate the influence of OA on the ACC formation in the shells of adult Mytilus edulis. Electron Backscatter Diffraction (EBSD) confirms that OA reduces crystallographic control of shell formation. The results demonstrate that OA induces more ACC formation and less crystallographic control in mussels suggesting that ACC is used as a repair mechanism to combat shell damage under OA. However, the resultant reduced crystallographic control in mussels raises concerns for shell protective function under predation and changing environments.
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| 5. |
- Krizek, Filip, et al.
(författare)
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Atomically sharp domain walls in an antiferromagnet
- 2022
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Ingår i: Science Advances. - : American Association for the Advancement of Science (AAAS). - 2375-2548. ; 8:13
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Tidskriftsartikel (refereegranskat)abstract
- The interest in understanding scaling limits of magnetic textures such as domain walls spans the entire field of magnetism from its physical fundamentals to applications in information technologies. Here, we explore antiferromagnetic CuMnAs in which imaging by x-ray photoemission reveals the presence of magnetic textures down to nanoscale, reaching the detection limit of this established microscopy in antiferromagnets. We achieve atomic resolution by using differential phase-contrast imaging within aberration-corrected scanning transmission electron microscopy. We identify abrupt domain walls in the antiferromagnetic film corresponding to the Néel order reversal between two neighboring atomic planes. Our work stimulates research of magnetic textures at the ultimate atomic scale and sheds light on electrical and ultrafast optical antiferromagnetic devices with magnetic field–insensitive neuromorphic functionalities.
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| 6. |
- Peden, Carol J., et al.
(författare)
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Enhanced Recovery After Surgery (ERAS®) Society Consensus Guidelines for Emergency Laparotomy Part 3 : Organizational Aspects and General Considerations for Management of the Emergency Laparotomy Patient
- 2023
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Ingår i: World Journal of Surgery. - : Springer. - 0364-2313 .- 1432-2323. ; 47:8, s. 1881-1898
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Forskningsöversikt (refereegranskat)abstract
- BACKGROUND: This is Part 3 of the first consensus guidelines for optimal care of patients undergoing emergency laparotomy using an enhanced recovery after surgery (ERAS) approach. This paper addresses organizational aspects of care.METHODS: Experts in management of the high-risk and emergency general surgical patient were invited to contribute by the International ERAS® Society. PubMed, Cochrane, Embase, and MEDLINE database searches were performed for ERAS elements and relevant specific topics. Studies were selected with particular attention to randomized clinical trials, systematic reviews, meta-analyses and large cohort studies, and reviewed and graded using the Grading of Recommendations, Assessment, Development and Evaluation system. Recommendations were made on the best level of evidence, or extrapolation from studies on elective patients when appropriate. A modified Delphi method was used to validate final recommendations.RESULTS: Components of organizational aspects of care were considered. Consensus was reached after three rounds of a modified Delphi process.CONCLUSIONS: These guidelines are based on best current available evidence for organizational aspects of an ERAS® approach to patients undergoing emergency laparotomy and include discussion of less common aspects of care for the surgical patient, including end-of-life issues. These guidelines are not exhaustive but pull together evidence on important components of care for this high-risk patient population. As much of the evidence is extrapolated from elective surgery or emergency general surgery (not specifically laparotomy), many of the components need further evaluation in future studies.
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| 7. |
- Peden, Carol J., et al.
(författare)
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Guidelines for Perioperative Care for Emergency Laparotomy Enhanced Recovery After Surgery (ERAS) Society Recommendations : Part 1-Preoperative: Diagnosis, Rapid Assessment and Optimization
- 2021
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Ingår i: World Journal of Surgery. - : Springer. - 0364-2313 .- 1432-2323. ; 45, s. 1272-1290
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Enhanced Recovery After Surgery (ERAS) protocols reduce length of stay, complications and costs for a large number of elective surgical procedures. A similar, structured approach appears to improve outcomes, including mortality, for patients undergoing high-risk emergency general surgery, and specifically emergency laparotomy. These are the first consensus guidelines for optimal care of these patients using an ERAS approach.METHODS: Experts in aspects of management of the high-risk and emergency general surgical patient were invited to contribute by the International ERAS® Society. Pubmed, Cochrane, Embase, and MEDLINE database searches on English language publications were performed for ERAS elements and relevant specific topics. Studies on each item were selected with particular attention to randomized controlled trials, systematic reviews, meta-analyses and large cohort studies, and reviewed and graded using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system. Recommendations were made on the best level of evidence, or extrapolation from studies on non-emergency patients when appropriate. The Delphi method was used to validate final recommendations. The guideline has been divided into two parts: Part 1-Preoperative Care and Part 2-Intraoperative and Postoperative management. This paper provides guidelines for Part 1.RESULTS: Twelve components of preoperative care were considered. Consensus was reached after three rounds.CONCLUSIONS: These guidelines are based on the best available evidence for an ERAS approach to patients undergoing emergency laparotomy. Initial management is particularly important for patients with sepsis and physiological derangement. These guidelines should be used to improve outcomes for these high-risk patients.
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| 8. |
- Reimers, Sonka, et al.
(författare)
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Defect-driven antiferromagnetic domain walls in CuMnAs films
- 2022
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- Efficient manipulation of antiferromagnetic (AF) domains and domain walls has opened up new avenues of research towards ultrafast, high-density spintronic devices. AF domain structures are known to be sensitive to magnetoelastic effects, but the microscopic interplay of crystalline defects, strain and magnetic ordering remains largely unknown. Here, we reveal, using photoemission electron microscopy combined with scanning X-ray diffraction imaging and micromagnetic simulations, that the AF domain structure in CuMnAs thin films is dominated by nanoscale structural twin defects. We demonstrate that microtwin defects, which develop across the entire thickness of the film and terminate on the surface as characteristic lines, determine the location and orientation of 180∘ and 90∘ domain walls. The results emphasize the crucial role of nanoscale crystalline defects in determining the AF domains and domain walls, and provide a route to optimizing device performance.
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| 9. |
- Reimers, Sonka, et al.
(författare)
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Defect-driven antiferromagnetic domain walls in CuMnAs films
- 2023
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Ingår i: 2023 IEEE International Magnetic Conference - Short Papers, INTERMAG Short Papers 2023 - Proceedings. - 9798350338362
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Konferensbidrag (refereegranskat)abstract
- Antiferromagnetic (AF) materials offer a route to realising high-speed, high-density data storage devices that are robust against magnetic fields due to their intrinsic dynamics in the THz-regime and the lack magnetic stray fields. The key to functionality and efficiency is the control of AF domains and domain walls. Although AF domain structures are known to be sensitive to magnetoelastic effects, the microscopic interplay of crystalline defects, strain and magnetic ordering remains largely unknown. Here, we reveal, using photoemission electron microscopy combined with scanning x-ray diffraction microscopy and micromagnetic simulations, that the AF domain structure in CuMnAs thin films is dominated by nanoscale structural twin defects, which determine the location and orientation of 180° and 90° domain walls. The results emphasise the high sensitivity of the AF domain structure to the crystallographic nanostructure and provide a route to optimisng device performance.
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| 10. |
- Scott, Michael J., et al.
(författare)
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Consensus Guidelines for Perioperative Care for Emergency Laparotomy Enhanced Recovery After Surgery (ERAS®) Society Recommendations Part 2-Emergency Laparotomy : Intra- and Postoperative Care
- 2023
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Ingår i: World Journal of Surgery. - : Springer. - 0364-2313 .- 1432-2323. ; 47:8, s. 1850-1880
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Forskningsöversikt (refereegranskat)abstract
- BACKGROUND: This is Part 2 of the first consensus guidelines for optimal care of patients undergoing emergency laparotomy (EL) using an Enhanced Recovery After Surgery (ERAS) approach. This paper addresses intra- and postoperative aspects of care.METHODS: Experts in aspects of management of high-risk and emergency general surgical patients were invited to contribute by the International ERAS® Society. PubMed, Cochrane, Embase, and Medline database searches were performed for ERAS elements and relevant specific topics. Studies on each item were selected with particular attention to randomized clinical trials, systematic reviews, meta-analyses, and large cohort studies and reviewed and graded using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system. Recommendations were made on the best level of evidence, or extrapolation from studies on elective patients when appropriate. A modified Delphi method was used to validate final recommendations. Some ERAS® components covered in other guideline papers are outlined only briefly, with the bulk of the text focusing on key areas pertaining specifically to EL.RESULTS: Twenty-three components of intraoperative and postoperative care were defined. Consensus was reached after three rounds of a modified Delphi Process.CONCLUSIONS: These guidelines are based on best available evidence for an ERAS® approach to patients undergoing EL. These guidelines are not exhaustive but pull together evidence on important components of care for this high-risk patient population. As much of the evidence is extrapolated from elective surgery or emergency general surgery (not specifically laparotomy), many of the components need further evaluation in future studies.
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