Micromagnetic modeling of magnetic nanostructures

... MICROMAGNETIC MODELING OF MAGNETIC NANOSTRUCTURES POOJA WADHWA (B.Sc.(Hons.), University of Delhi, India) A THESIS SUBMITTED FOR THE DEGREE OF MASTER OF ENGINEERING DEPARTMENT OF ELECTRICAL ... Jalil, Micromagnetic modeling and analysis of linear array of square nanomagnets”, is in press in Journal of Magnetism and Magnetic Materials, 2004 Pooja Wadhwa and M.B.A J...

Ngày tải lên: 26/11/2015, 12:15

... considered as one of the main gaps for bit patterned media Therefore, the main focus of this thesis lies in understanding the switching field distribution of patterned magnetic media and its correlation ... 2.5.2.4 Hypothesis of PMA-MFM tip 37 2.5.2.5 Resolving of magnetic domains in granular media 38 2.5.2.6 Resolving of magnetic island for bit patterned m...

Ngày tải lên: 09/09/2015, 10:19

... review on the magnetic nanostructures and their applications will be provided in the following sections 1.1 Micromagnetics 1.1.1 Theory of Operation Chapter 1: Introduction Micromagnetic simulation ... description of the time evolution of spin configuration With the help of micromagnetic simulation, we can obtain direct visualization of magnetization configurations, static...

Ngày tải lên: 09/09/2015, 11:30

... STUDY OF MAGNETIC NANOSTRUCTURES FABRICATED BY NANOSPHERE LITHOGRAPHY VERMA LALIT KUMAR (M Sc Electronics, University of Delhi, India) A THESIS SUBMITTED FOR THE DEGREE OF DOCTOR OF PHILOSOPHY ... of size and shape on the magnetic properties of unique nanostructures fabricated by our modified nanosphere lithography methods, and further explore the limits...

Ngày tải lên: 12/09/2015, 08:16

... phenomenon of superparamagnetism whereby magnetic grains behave like paramagnetic atoms at high temperature due to thermal agitation [4] The changes of magnetization configuration in magnetic grains ... information We can change the information stored within magnetic grains by applying a magnetic field to change the state of M A strong uniaxial magnetic field can align M o...

Ngày tải lên: 26/09/2015, 09:56

... between these two parameters can be reduced when the permeability of the magnetic materials is high 1. 1.3 Snoek’s law For soft magnetic bulk materials, the product of the intrinsic permeability μi and ... μi at microwave frequency band There is another expression of Snoek’s law for planar materials, which is given as[8] 1/ 2 H (μi − 1) fr = γ4πMs ( ) H ea (1. 11) whe...

Ngày tải lên: 08/09/2015, 19:41

... ZF2 12 Zn0 .29 0Fe2.710O4 28 20 ZF3 12 Zn0.387Fe2.613O4 28 20 ZF3 _26 .5 Zn0.38Fe2.62O4 28 20 ZF3_13.4 7 .2 3.6 Zn0.38Fe2.62O4 28 20 ZF4 12 Zn0.468Fe2.532O4 28 20 ZF5 12 10 Zn0. 522 Fe2.478O4 28 20 ... 20 ZF6 12 12 Zn0. 524 Fe2.476O4 28 20 ZF7 12 14 Zn0. 527 Fe2.472O4 28 20 Note: The particle sizes of samples ZF0 to ZF7 are all around 100nm, while the particle s...

Ngày tải lên: 08/09/2015, 19:42

... ratio of Fe to Si about 5.4 Fig 3. 2(e1, e2, e3 and e4) are elemental mappings of C, O, Fe and Si, respectively, as labeled in the images The carbon shown in both of the EDS spectrum and the mapping ... surface of Fe particles is also evidenced by the EDS spectrum and elemental mapping The chemical analysis from the EDS spectrum in Fig 3. 2d 47 Chapter Synthes...

Ngày tải lên: 08/09/2015, 19:43

... and the wall of the chamber The larger particles of the product get retained at the periphery of the chamber by centrifugal force and the smaller particles exit from the central port of the chamber ... ball milling and jet milling routes Fig 4. 11 The relationship of electromagnetic parameters and frequency in the range of 0.1~18 GHz:(a) and (b) ar...

Ngày tải lên: 08/09/2015, 19:44

... monitoring the change in the magnetic moment 74 Chapter Size controllable synthesis of octahedral Fe3O4 nanoparticles and the microwave absorbing properties of the reaction solution during the synthesis ... nm Fig 5. 5 TEM images of the as-obtained Fe3O4 nanoparticles by reducing the concentration of oleic acid: A) 0. 35, B) 0.19, C) 0.10 and D-E) 0.07 M 5....

Ngày tải lên: 08/09/2015, 19:44

... in the developed synthesis method That’s why we use 12 mmol of Fe precursor as the starting materials for the study on synthesis of Zn ferrites 6. 2.3 Microwave absorption performance of as-synthesized ... chapter 6. 2 Experimental results 6. 2.1 Synthesis and characterizations on large size Zn-ferrite nanoparticles 6. 2.1.1 Effect of the molar ratio of Zn pr...

Ngày tải lên: 08/09/2015, 19:45

... (c) 70 nm -Fe2O3 tubes and (d) 98 nm -Fe2O3 rod The scale bars for all the images stand for 200 nm 7. 2.1.3 Size controllable synthesis of -Fe2O3 rods For the synthesis of -Fe2O3 rods, the ... comparing the SEM images of sample E (Fig 7. 7a) and D (Fig 7. 5d), we could find that the usage of 5%H2/95%Ar gas made a great improvement on the surface morpholog...

Ngày tải lên: 08/09/2015, 19:46

... frequency band Compared to the spherical Fe/Al alloys, the Fe/Al flakes show two advantages on the microwave absorption The one is that the thickness of the flakes is rather smaller than the skin ... future, the use of jet milling for the synthesis of submicron Fe/Al flakes may be tried on other materials (2) The thermal decomposition method is adopted to synthes...

Ngày tải lên: 08/09/2015, 19:46

... illustration of a VSM system Fig 2.6 The effects of (a) the isomer shift; (b) the quadrupole splitting and (c) the magnetic splitting on the nuclear energy levels of 57 Fe The Mössbauer absorptions and the ... parameters and frequency in the range of 0.1~18 GHz:(a) and (b) are the real and imaginary part of measured complex permittivity, respectively; (...

Ngày tải lên: 08/09/2015, 19:47

... SYNTHESIS OF SUPERPARMAGNETIC NANOSTRUCTURES AND THEIR MAGNETIC RESONANCE IMAGING APPLICATIONS CHOO SHI GUANG, EUGENE (B APPL SCI., HONS), NUS A THESIS SUBMITTED FOR THE DEGREE OF DOCTOR OF ... Study of Magnetic Nanostructures for Off -Resonance MR Spectroscopic Imaging 127  6.1  Motivations and Design of Experiment 127  6.2  Preparation and Characterizati...

Ngày tải lên: 09/09/2015, 17:55