Aromatic and antiaromatic spherical structures: use of long-range magnetic behavior as an aromatic indicator for bare icosahedral [Al@Al12]− and [Si12]2− clusters

2017 ◽  
Vol 19 (24) ◽  
pp. 15667-15670 ◽  
Author(s):  
A. Muñoz-Castro ◽  
R. Bruce King
Keyword(s):  
Long Range ◽  
Magnetic Behavior ◽  
Spherical Structures ◽  
Endohedral Clusters ◽  
Antiaromatic Character

Long-range magnetic behavior unravels aromatic/antiaromatic character equally in hollow or endohedral clusters.

scholarly journals From intermediate valence to magnetic behavior without long-range order by hydrogenation of the ternary gallide CeNiGa

2005 ◽  
Vol 71 (21) ◽  
Author(s):  
B. Chevalier ◽  
J. Sanchez Marcos ◽  
J. Rodriguez Fernandez ◽  
M. Pasturel ◽  
F. Weill
Keyword(s):  
Long Range ◽  
Magnetic Behavior ◽  
Range Order ◽  
Long Range Order ◽  
Intermediate Valence

Cu(HCO2)2(pym) (pym = pyrimidine):  Low-Dimensional Magnetic Behavior and Long-Range Ordering in a Quantum-Spin Lattice

2005 ◽  
Vol 44 (4) ◽  
pp. 989-995 ◽  
Author(s):  
J. L. Manson ◽  
T. Lancaster ◽  
L. C. Chapon ◽  
S. J. Blundell ◽  
J. A. Schlueter ◽  
...  
Keyword(s):  
Long Range ◽  
Magnetic Behavior ◽  
Quantum Spin ◽  
Spin Lattice ◽  
Long Range Ordering ◽  
Low Dimensional

scholarly journals Single Diameter Modulation Effects on Ni Nanowire Array Magnetization Reversal

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3403
Author(s):  
Luis C. C. Arzuza ◽  
Victor Vega ◽  
Victor M. Prida ◽  
Karoline O. Moura ◽  
Kleber R. Pirota ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Domain Wall ◽  
Long Range ◽  
Magnetization Reversal ◽  
Nanowire Array ◽  
Magnetic Behavior ◽  
Nanowire Arrays ◽  
Magnetic Nanowires ◽  
Range Interaction ◽  
Domain Wall Propagation

Geometrically modulated magnetic nanowires are a simple yet efficient strategy to modify the magnetic domain wall propagation since a simple diameter modulation can achieve its pinning during the nanowire magnetization reversal. However, in dense systems of parallel nanowires, the stray fields arising at the diameter interface can interfere with the domain wall propagation in the neighboring nanowires. Therefore, the magnetic behavior of diameter-modulated nanowire arrays can be quite complex and depending on both short and long-range interaction fields, as well as the nanowire geometric dimensions. We applied the first-order reversal curve (FORC) method to bi-segmented Ni nanowire arrays varying the wide segment (45–65 nm diameter, 2.5–10.0 μm length). The FORC results indicate a magnetic behavior modification depending on its length/diameter aspect ratio. The distributions either exhibit a strong extension along the coercivity axis or a main distribution finishing by a fork feature, whereas the extension greatly reduces in amplitude. With the help of micromagnetic simulations, we propose that a low aspect ratio stabilizes pinned domain walls at the diameter modulation during the magnetization reversal. In this case, long-range axial interaction fields nucleate a domain wall at the nanowire extremities, while short-range ones could induce a nucleation at the diameter interface. However, regardless of the wide segment aspect ratio, the magnetization reversal is governed by the local radial stray fields of the modulation near null magnetization. Our findings demonstrate the capacity of distinguishing between complex magnetic behaviors involving convoluted interaction fields.

Video real-time imaging of artificial membranes during freeze-drying by cryo-electron microscopy

1988 ◽  
Vol 46 ◽  
pp. 16-17
Author(s):  
Alan S. Rudolph ◽  
Ronald R. Price
Keyword(s):  
Real Time ◽  
Self Assembly ◽  
Freeze Drying ◽  
Video Capture ◽  
Drying Process ◽  
Artificial Membranes ◽  
The Past ◽  
Cryo Electron Microscopy ◽  
Spherical Structures ◽  
Capture Techniques

We have employed cryoelectron microscopy to visualize events that occur during the freeze-drying of artificial membranes by employing real time video capture techniques. Artificial membranes or liposomes which are spherical structures within internal aqueous space are stabilized by water which provides the driving force for spontaneous self-assembly of these structures. Previous assays of damage to these structures which are induced by freeze drying reveal that the two principal deleterious events that occur are 1) fusion of liposomes and 2) leakage of contents trapped within the liposome [1]. In the past the only way to access these events was to examine the liposomes following the dehydration event. This technique allows the event to be monitored in real time as the liposomes destabilize and as water is sublimed at cryo temperatures in the vacuum of the microscope. The method by which liposomes are compromised by freeze-drying are largely unknown. This technique has shown that cryo-protectants such as glycerol and carbohydrates are able to maintain liposomal structure throughout the drying process.

Lorentz electron microscopy of magnetic domains in rapidly solidified and annealed Pt-Co-B alloys

1991 ◽  
Vol 49 ◽  
pp. 784-785
Author(s):  
N. Qiu ◽  
J. E. Wittig
Keyword(s):  
Rapid Solidification ◽  
Ion Beam ◽  
Magnetic Behavior ◽  
High Coercivity ◽  
Magnetic Domains ◽  
Beam Angle ◽  
Tem Analysis ◽  
Intrinsic Coercivity ◽  
Hard Magnets ◽  
Rapidly Solidified

PtCo hard magnets have specialized applications owing to their relatively high coercivity combined with corrosion resistance and ductility. Increased intrinsic coercivity has been recently obtained by rapid solidification processing of PtCo alloys containing boron. After rapid solidification by double anvil splat quenching and subsequent annealing for 30 minutes at 650°C, an alloy with composition Pt42Co45B13 (at.%) exhibited intrinsic coercivity up to 14kOe. This represents a significant improvement compared to the average coercivities in conventional binary PtCo alloys of 5 to 8 kOe.Rapidly solidified specimens of Pt42Co45B13 (at.%) were annealed at 650°C and 800°C for 30 minutes. The magnetic behavior was characterized by measuring the coercive force (Hc). Samples for TEM analysis were mechanically thinned to 100 μm, dimpled to about 30 nm, and ion milled to electron transparency in a Gatan Duomill at 5 kV and 1 mA gun current. The incident ion beam angle was set at 15° and the samples were liquid nitrogen cooled during milling. These samples were analyzed with a Philips CM20T TEM/STEM operated at 200 kV.

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