Large-area patterned magnetic nanostructures by self-assembling of polystyrene nanospheres

2012 ◽  
Vol 1411 ◽  
Author(s):  
Paola Tiberto ◽  
Luca Boarino ◽  
Federica Celegato ◽  
Gabriele Barrera ◽  
Marco Coisson ◽  
...  
Keyword(s):  
Magnetic Nanostructures ◽  
Magnetic Domain ◽  
Hysteresis Loops ◽  
Gradient Field ◽  
Temperature Hysteresis ◽  
Mutual Distance ◽  
Large Area ◽  
Advantages And Disadvantages ◽  
Self Assembling ◽  
Polystyrene Nanospheres

ABSTRACTIn this work, dot and anti-dot structures in Co, Ni, Ni80Fe20, Fe50Pd50, Fe73.5Cu1Nb3Si13.5B9 and Fe78B13Si9 thin films have been produced by means of nanosphere lithography. Two multi-step processes have been followed and will be here described. The first one directly exploits polystyrene nanosheres (PN) as a mask to fabricate arrays of magnetic nanoholes and dots. In the second case, the nanospheres are used to design a polymeric mask of a photoresist subsequently used to pattern a magnetic nanostructure on a film. Advantages and disadvantages of the two lithographical techniques will be here highlighted. In both processes, the dimension and mutual distance of the patterns are dependent on the starting PN diameter (in the interval 500-800 nm). Samples microstructure has been studied by means of SEM and AFM microscopy. Room-temperature hysteresis loops have been measured by an AGFM (Alternating Gradient Field Magnetometer). MFM microscopy has been exploited to study the magnetic domain pattern. All produced systems have been observed to display tunable microstructure and, consequently, various magnetic properties for application.

scholarly journals Surface modification and cellular uptake evaluation of Au-coated Ni 80 Fe 20 nanodiscs for biomedical applications

2016 ◽  
Vol 6 (6) ◽  
pp. 20160052 ◽  
Author(s):  
Gabriele Barrera ◽  
Loredana Serpe ◽  
Federica Celegato ◽  
Marco Coїsson ◽  
Katia Martina ◽  
...  
Keyword(s):  
Biomedical Applications ◽  
Vortex Formation ◽  
Fluorescein Isothiocyanate ◽  
Gold Surface ◽  
Gold Layer ◽  
Temperature Hysteresis ◽  
Free Standing ◽  
Self Assembling ◽  
Polystyrene Nanospheres ◽  
Nanofabrication Technique

A nanofabrication technique based on self-assembling of polystyrene nanospheres is used to obtain magnetic Ni 80 Fe 20 nanoparticles with a disc shape. The free-standing nanodiscs (NDs) have diameter and thickness of about 630 nm and 30 nm, respectively. The versatility of fabrication technique allows one to cover the ND surface with a protective gold layer with a thickness of about 5 nm. Magnetization reversal has been studied by room-temperature hysteresis loop measurements in water-dispersed free-standing NDs. The reversal shows zero remanence, high susceptibility and nucleation/annihilation fields due to spin vortex formation. In order to investigate their potential use in biomedical applications, the effect of NDs coated with or without the protective gold layer on cell growth has been evaluated. A successful attempt to bind cysteine-fluorescein isothiocyanate (FITC) derivative to the gold surface of magnetic NDs has been exploited to verify the intracellular uptake of the NDs by cytofluorimetric analysis using the FITC conjugate.

scholarly journals Two-Dimensional Materials in Large-Areas: Synthesis, Properties and Applications

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Ali Zavabeti ◽  
Azmira Jannat ◽  
Li Zhong ◽  
Azhar Ali Haidry ◽  
Zhengjun Yao ◽  
...  
Keyword(s):  
Two Dimensional ◽  
Large Area ◽  
Large Crystal ◽  
High Quality ◽  
Future Technology ◽  
Advantages And Disadvantages ◽  
Grain Sizes ◽  
Two Dimensional Materials ◽  
Synthesis Properties ◽  
Synthetic Routes

AbstractLarge-area and high-quality two-dimensional crystals are the basis for the development of the next-generation electronic and optical devices. The synthesis of two-dimensional materials in wafer scales is the first critical step for future technology uptake by the industries; however, currently presented as a significant challenge. Substantial efforts have been devoted to producing atomically thin two-dimensional materials with large lateral dimensions, controllable and uniform thicknesses, large crystal domains and minimum defects. In this review, recent advances in synthetic routes to obtain high-quality two-dimensional crystals with lateral sizes exceeding a hundred micrometres are outlined. Applications of the achieved large-area two-dimensional crystals in electronics and optoelectronics are summarised, and advantages and disadvantages of each approach considering ease of the synthesis, defects, grain sizes and uniformity are discussed.

Large area magnetic domain imaging of magnetite films with Spin-SEM

2007 ◽  
Vol 4 (12) ◽  
pp. 4364-4367 ◽  
Author(s):  
Eisaku Kaji ◽  
Agus Subagyo ◽  
Kazuhisa Sueoka
Keyword(s):  
Magnetic Domain ◽  
Large Area

Exploring the Open Problems and Future Trends Concerning Handovers in Heterogeneous Wireless Networks: A Review

2014 ◽  
Vol 70 (3) ◽  
Author(s):  
Bushra Naeem ◽  
Uche A. K. Chude-Okonkwo ◽  
Razali Ngah ◽  
Siti Z. Mohd Hashim ◽  
Wajahat Maqbool ◽  
...  
Keyword(s):  
Wireless Networks ◽  
Communication Systems ◽  
New Technologies ◽  
Heterogeneous Wireless Networks ◽  
Future Trends ◽  
Large Area ◽  
Open Problems ◽  
Advantages And Disadvantages ◽  
Seamless Connectivity ◽  
Vertical Handovers

The advancements in the telecoms industry have led to the emergence of many new technologies to meet communication requirements worldwide. Consumers have largely been using GSM, CDMA and WiFi. New developments have given birth to more robust communication systems including WiMax and LTE. Lay users are not aware of the technicalities, advantages and disadvantages of these technologies. Therefore, there is a state of great confusion among the users of this generation as to which technology is the best for them to use. Each of these technologies has pros and cons over one another. For example, LTE covers a large area and offers the highest speed, but the user has to pay for it; however, WiFi covers only hotspots but the use is free. Future heterogeneous networks (HetNets) will enable users to achieve seamless connectivity through vertical handovers while providing them the beneficial features of each technology. For HetNets many issues still need to be addressed. This paper explores some of the open problems and future trends related to the handovers in heterogeneous wireless networks. The dynamics with respect to handovers and the network load of cellular architecture in the coming era in the field of wireless communications are also presented. In addition, first a foundation is laid on the IEEE media independent handover and its importance and then the problem of load balancing and its impact on the realization of future HetNets is explained. Finally, an important problem during vertical handovers, known as the ping-pong effect is explained. The open problems for researchers have been identified for the aforementioned issues.

Electrical Properties of Polymer Composites

2005 ◽  
Vol 482 ◽  
pp. 391-394
Author(s):  
T. Podgrabinski ◽  
Petr Slepička ◽  
V. Rybka ◽  
Václav Švorčík
Keyword(s):  
Thin Films ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Electrical Properties ◽  
Hysteresis Loops ◽  
Temperature Hysteresis ◽  
Electrical Field ◽  
Measured Polarization ◽  
Pmma Solution

Permittivity of about 1 µm thin films prepared from polymethylmetactrylate (PMMA) solution doped with 20 % of diphenyl sulfoxide was studied. Permittivity of the films was measured as a function of the temperature. The measurement of the dependence of polarization on electrical field was performed using a standard Sawyer-Tower circuit. The presence of the dopant increases the composite permittivity namely above the PMMA glass transition temperature. Hysteresis loops observed on the measured polarization vs. electrical field dependence indicate easier and more pronounced polarizability of the composite comparing to pristine PMMA.

scholarly journals Magnetization reversal and microstructure in polycrystalline Fe50Pd50 dot arrays by self-assembling of polystyrene nanospheres

2016 ◽  
Vol 17 (1) ◽  
pp. 462-472 ◽  
Author(s):  
Paola Tiberto ◽  
Federica Celegato ◽  
Gabriele Barrera ◽  
Marco Coisson ◽  
Franco Vinai ◽  
...  
Keyword(s):  
Magnetization Reversal ◽  
Self Assembling ◽  
Polystyrene Nanospheres

Arrays of ordered nanostructures in Fe-Pt thin films by self-assembling of polystyrene nanospheres

2013 ◽  
Vol 113 (17) ◽  
pp. 17B516 ◽  
Author(s):  
Paola Tiberto ◽  
Gabriele Barrera ◽  
Luca Boarino ◽  
Federica Celegato ◽  
Marco Coïsson ◽  
...  
Keyword(s):  
Thin Films ◽  
Self Assembling ◽  
Polystyrene Nanospheres ◽  
Ordered Nanostructures

scholarly journals Micromagnetic Simulation of L10-FePt-Based Exchange-Coupled-Composite-Bit-Patterned Media with Microwave-Assisted Magnetic Recording at Ultrahigh Areal Density

Micromachines ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1264
Author(s):  
Pirat Khunkitti ◽  
Naruemon Wannawong ◽  
Chavakon Jongjaihan ◽  
Apirat Siritaratiwat ◽  
Anan Kruesubthaworn ◽  
...  
Keyword(s):  
Magnetic Recording ◽  
Magnetic Domain ◽  
Hysteresis Loops ◽  
Areal Density ◽  
Bit Patterned Media ◽  
Patterned Media ◽  
Microwave Assisted ◽  
The Media ◽  
5 Ghz ◽  
Exchange Coupled Composite

In this work, we propose exchange-coupled-composite-bit-patterned media (ECC-BPM) with microwave-assisted magnetic recording (MAMR) to improve the writability of the magnetic media at a 4 Tb/in2 recording density. The suitable values of the applied microwave field’s frequency and the exchange coupling between magnetic dots, Adot, of the proposed media were evaluated. It was found that the magnitude of the switching field, Hsw, of the bilayer ECC-BPM is significantly lower than that of a conventional BPM. Additionally, using the MAMR enables further reduction of Hsw of the ECC-BPM. The suitable frequency of the applied microwave field for the proposed media is 5 GHz. The dependence of Adot on the Hsw was additionally examined, showing that the Adot of 0.14 pJ/m is the most suitable value for the proposed bilayer ECC-BPM. The physical explanation of the Hsw of the media under a variation of MAMR and Adot was given. Hysteresis loops and the magnetic domain of the media were characterized to provide further details on the results. The lowest Hsw found in our proposed media is 12.2 kOe, achieved by the bilayer ECC-BPM with an Adot of 0.14 pJ/m using a 5 GHz MAMR.

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