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Yang S, Feng C, Spence D, Al Hindawi AMAA, Latimer E, Ellis AM, Binns C, Peddis D, Dhesi SS, Zhang L, Zhang Y, Trohidou KN, Vasilakaki M, Ntallis N, MacLaren I, de Groot FMF. Robust Ferromagnetism of Chromium Nanoparticles Formed in Superfluid Helium. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017; 29:1604277. [PMID: 27787938 DOI: 10.1002/adma.201604277] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 09/19/2016] [Indexed: 06/06/2023]
Abstract
Chromium nanoparticles are formed using superfluid helium droplets as the nanoreactors, which are strongly ferromagnetic. The transition from antiferromagentism to ferromagnetism is attributed to atomic-scale disorder in chromium nanoparticles, leading to abundant unbalanced surface spins. Theoretical modeling confirms a frustrated aggregation process in superfluid helium due to the antiferromagnetic nature of chromium.
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Affiliation(s)
- Shengfu Yang
- Department of Chemistry, University of Leicester, Leicester, LE1 7RH, UK
| | - Cheng Feng
- Department of Chemistry, University of Leicester, Leicester, LE1 7RH, UK
| | - Daniel Spence
- Department of Chemistry, University of Leicester, Leicester, LE1 7RH, UK
| | | | - Elspeth Latimer
- Department of Chemistry, University of Leicester, Leicester, LE1 7RH, UK
| | - Andrew M Ellis
- Department of Chemistry, University of Leicester, Leicester, LE1 7RH, UK
| | - Chris Binns
- Department of Physics and Astronomy, University of Leicester, Leicester, LE1 7RH, UK
| | - Davide Peddis
- Institute of Structure of Matter, National Research Council (CNR), 00015, Monterotondo Scalo, Italy
| | - Sarnjeet S Dhesi
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 0DE, UK
| | - Liying Zhang
- School of Electronics, Information and Electrical Engineering, Shanghai Jiaotong University, Shanghai, 200240, China
| | - Yafei Zhang
- School of Electronics, Information and Electrical Engineering, Shanghai Jiaotong University, Shanghai, 200240, China
| | - Kalliopi N Trohidou
- Institute of Nanoscience and Nanotechnology, NCSR Demokritos, 153 10, Aghia, Greece
| | - Marianna Vasilakaki
- Institute of Nanoscience and Nanotechnology, NCSR Demokritos, 153 10, Aghia, Greece
| | - Nikolaos Ntallis
- Institute of Nanoscience and Nanotechnology, NCSR Demokritos, 153 10, Aghia, Greece
- Department of Physics, Aristotle University, 54124, Thessaloniki, Greece
| | - Ian MacLaren
- Department of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Frank M F de Groot
- Department of Chemistry, Utrecht University, Universiteitsweg 99, 3584CG, Utrecht, The Netherlands
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Bury I, Heinrich B, Bourgogne C, Guillon D, Donnio B. Supramolecular Self-Organization of “Janus-like” Diblock Codendrimers: Synthesis, Thermal Behavior, and Phase Structure Modeling. Chemistry 2006; 12:8396-413. [PMID: 16892472 DOI: 10.1002/chem.200600449] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
We report on the design and synthesis of three series of segmented amphiphilic block codendrimers, and on their self-organizing behavior in liquid-crystalline mesophases. Connecting two prefunctionalized monodendrons, each differing in their chemical constitution and generation number, yielded these diblock supermolecules. One wedge of the codendrimer was made hydrophobic, and is based on a branched poly(benzyl ether) monodendron functionalized at the periphery by lipophilic aliphatic fragments (also known as Percec dendrons). The other segment was made hydrophilic by the grafting of hydroxyl-containing moieties onto the focal functions of the former dendrons. Both types of dendrons were prepared independently by convergent methods and then joined in the ultimate stage of the synthetic procedure by cross-coupling reactions. In this way, the proportion of the dendritic blocks was varied independently to allow control of the hydrophilic/hydrophobic balance (HHB), the hydrogen-bonding ability, and consequently the capacity to tune the mesomorphic properties of the resulting "superamphiphiles" was anticipated. Essentially all the dendritic compounds display a thermotropic mesomorphism directly at or near room temperature as determined by using X-ray diffraction, polarized optical microscopy, and differential scanning calorimetry. The nature and the supramolecular organization of the mesophases, namely columnar and cubic phases, are correlated to the size of the respective block monodendrons and the chemical structures of the dendromesogens. The molecular organization within the cubic phases can be geometrically described and well understood by the space-filling polyhedron model.
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Affiliation(s)
- Izabela Bury
- Institut de Physique et Chimie des Matériaux de Strasbourg, Groupe des Matériaux Organiques, UMR 7504-CNRS/Université Louis Pasteur, 23 rue du Loess, BP 43, 67034 Strasbourg Cedex 2, France
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Fitzsimmons MR, Eastman JA, Thompson LJ. Roles of grain size and strain on antiferromagnetic order in nanocrystalline chromium. PHYSICAL REVIEW. B, CONDENSED MATTER 1994; 50:5600-5608. [PMID: 9976904 DOI: 10.1103/physrevb.50.5600] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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