scholarly journals Microresonators and Microantennas—Tools to Explore Magnetization Dynamics in Single Nanostructures

2021 ◽  
Vol 7 (2) ◽  
pp. 28
Author(s):  
Hamza Cansever ◽  
Jürgen Lindner
Keyword(s):  
Magnetic Resonance ◽  
Spin Wave ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Relaxation Times ◽  
Magnetic Nanostructures ◽  
Microwave Frequency ◽  
Direct Access ◽  
Magnetization Dynamics ◽  
G Factor

The phenomenon of magnetic resonance and its detection via microwave spectroscopy provide insight into the magnetization dynamics of bulk or thin film materials. This allows for direct access to fundamental properties, such as the effective magnetization, g-factor, magnetic anisotropy, and the various damping (relaxation) channels that govern the decay of magnetic excitations. Cavity-based and broadband ferromagnetic resonance techniques that detect the microwave absorption of spin systems require a minimum magnetic volume to obtain a sufficient signal-to-noise ratio (S/N). Therefore, conventional techniques typically do not offer the sensitivity to detect individual micro- or nanostructures. A solution to this sensitivity problem is the so-called planar microresonator, which is able to detect even the small absorption signals of magnetic nanostructures, including spin-wave or edge resonance modes. As an example, we describe the microresonator-based detection of spin-wave modes within microscopic strips of ferromagnetic A2 Fe60Al40 that are imprinted into a paramagnetic B2 Fe60Al40-matrix via focused ion-beam irradiation. While microresonators operate at a fixed microwave frequency, a reliable quantification of the key magnetic parameters like the g-factor or spin relaxation times requires investigations within a broad range of frequencies. Furthermore, we introduce and describe the step from microresonators towards a broadband microantenna approach. Broadband magnetic resonance experiments on single nanostructured magnetic objects in a frequency range of 2–18 GHz are demonstrated. The broadband approach has been employed to explore the influence of lateral structuring on the magnetization dynamics of a Permalloy (Ni80Fe20) microstrip.

scholarly journals Magnetic Nanostructures Patterned by Focused Ion Beam in an ultrathin Pt/Co/Pt film

2002 ◽  
Vol 2 (4) ◽  
pp. 175-178 ◽  
Author(s):  
R. Hyndman ◽  
A. Mougin ◽  
V. Repain ◽  
J. Ferre ◽  
J.P. Jamet ◽  
...  
Keyword(s):  
Focused Ion Beam ◽  
Ion Beam ◽  
Magnetic Nanostructures

Microwave Frequency Signal Propagation in Backside Focused Ion Beam (FIB) Fabricated Interconnects

2002 ◽  
Author(s):  
Jeremy A. Rowlette ◽  
M. DiBattista ◽  
Seth Fortuna ◽  
Richard H. Livengood
Keyword(s):  
Flip Chip ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Microwave Frequency ◽  
Signal Propagation ◽  
Element Model ◽  
Cmos Technology ◽  
Propagation Delay ◽  
Digital Signals ◽  
Circuit Element

Abstract We present for the first time the results of a comprehensive study of the increase in propagation delay of multi-GHz digital signals due to backside FIB fabricated interconnects. Signal propagation delays were measured in 90nm CMOS technology circuits as a function of interconnect material properties and physical dimensions. We compare the empirical results of this study to SPICE calculations, which were based on an equivalent circuit element model of the interconnect. We show that the empirical data obtained in these experiments supports the validity of the equivalent electrical model for the frequency range typically encountered in modern microprocessor debug. Based on the results or our analysis, we comment on the future capability of backside FIB circuit edit (CE) interconnection technology as it pertains to the debug of flip-chip packaged IC’s operating at multi-GHz frequency.

Fabrication of Magnetic Nanostructures for MRAM using Electron Beam and Focused Ion Beam Exposure of HSQ

2006 ◽  
Vol 961 ◽  
Author(s):  
Chen Chen ◽  
Michael J Cabral ◽  
Robert Hull ◽  
Lloyd R Harriott
Keyword(s):  
Electron Beam ◽  
High Speed ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Random Access ◽  
Magnetic Nanostructures ◽  
Argon Plasma ◽  
Memory Cell ◽  
Direct Write ◽  
Good Signal

ABSTRACTGiant magnetoresistive (GMR) materials-based magnetic random access memory (MRAM) has become attractive due to non-volatility, speed and density1. The vertical MRAM (VMRAM) design model shows good signal level and high speed and density potential. The memory cell for the VMRAM model is a ring shaped magnetic material multilayer, which ensures high repeatability and low switching energy. This GMR structure, however, is difficult to pattern as it contains materials such as Ni, Fe, Co, and Cu, which are difficult to dry etch because they lack volatile etch products. This work shows that it is possible to overcome the difficulties associated with etching GMR materials by using hydrogen silsesquioxane (HSQ) as an etch mask. We have used HSQ in a direct-write electron-beam lithography system with a dose of 600 μC/cm2, and in a Ga+ ion focused ion beam (FIB) system with a dose of 12 μC/cm2. Both are followed by development and an argon plasma etch at 10mTorr and 100W RIE power. The HSQ layer provides high resolution as well as good etching resistance. Electron-beam exposed HSQ shows a 1:1.5 selectivity over the GMR film stack and the FIB exposed HSQ showed an improved etch selectivity of 1:1. Ring shaped GMR structures with a 75/225 nm (ID/OD) have been fabricated, which corresponds to a memory density of 4Gb/in2.

An emerging technology: Nuclear magnetic resonance microscopy

1988 ◽  
Vol 46 ◽  
pp. 1000-1001
Author(s):  
M.J. Hennessy ◽  
E. Kwok
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Relaxation Times ◽  
Basic Research ◽  
Local Environment ◽  
Magnetic Resonance Images ◽  
Nmr Microscopy ◽  
Mri Scans ◽  
Temperature Relaxation ◽  
Nuclear Magnetic

Much progress in nuclear magnetic resonance microscope has been made in the last few years as a result of improved instrumentation and techniques being made available through basic research in magnetic resonance imaging (MRI) technologies for medicine. Nuclear magnetic resonance (NMR) was first observed in the hydrogen nucleus in water by Bloch, Purcell and Pound over 40 years ago. Today, in medicine, virtually all commercial MRI scans are made of water bound in tissue. This is also true for NMR microscopy, which has focussed mainly on biological applications. The reason water is the favored molecule for NMR is because water is,the most abundant molecule in biology. It is also the most NMR sensitive having the largest nuclear magnetic moment and having reasonable room temperature relaxation times (from 10 ms to 3 sec). The contrast seen in magnetic resonance images is due mostly to distribution of water relaxation times in sample which are extremely sensitive to the local environment.

Nanocomposite Polyurethane Foams Via POSS Blends

2002 ◽  
Vol 733 ◽  
Author(s):  
Brock McCabe ◽  
Steven Nutt ◽  
Brent Viers ◽  
Tim Haddad
Keyword(s):  
High Temperature ◽  
Sample Preparation ◽  
Room Temperature ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Polyurethane Foams ◽  
Development Projects ◽  
Polymer Systems ◽  
Polyurethane Resin ◽  
Military Development

AbstractPolyhedral Oligomeric Silsequioxane molecules have been incorporated into a commercial polyurethane formulation to produce nanocomposite polyurethane foam. This tiny POSS silica molecule has been used successfully to enhance the performance of polymer systems using co-polymerization and blend strategies. In our investigation, we chose a high-temperature MDI Polyurethane resin foam currently used in military development projects. For the nanofiller, or “blend”, Cp7T7(OH)3 POSS was chosen. Structural characterization was accomplished by TEM and SEM to determine POSS dispersion and cell morphology, respectively. Thermal behavior was investigated by TGA. Two methods of TEM sample preparation were employed, Focused Ion Beam and Ultramicrotomy (room temperature).

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