jap banner
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Flickr Twitter iResearch App Facebook

SECTION LISTING

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Previous Issue Next Issue

1 Jun 2004

Volume 95, Issue 11, pp. 5949-7559

Return to All Sections
back to top
RSS Feeds
back to top Artificially Structured Materials III: Patterned Structures

A study of magnetic interactions of Ni80Fe20 arrays using ultrasensitive microcantilever torque magnetometry

L. Gao, D. Q. Feng, L. Yuan, T. Yokota, R. Sabirianov, S. H. Liou, M. D. Chabot, D. Porpora, and J. Moreland

J. Appl. Phys. 95, 7010 (2004); http://dx.doi.org/10.1063/1.1682912 (3 pages) | Cited 3 times

Online Publication Date: 25 May 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have successfully fabricated single and paired 300 nm×1.5 μm×32 nm Ni80Fe20 bars on a microcantilever using focused ion beam milling. Magnetic interactions of the paired bars were studied by using magnetic force microscopy, microcantilever torque magnetometry, and micromagnetic simulation. Our results clearly indicate that the magnetic switching behavior of the paired Ni80Fe20 bars is affected by magnetostatic interactions. The magnetic hysteresis curves for a sample with eight pairs of Ni80Fe20 bars consist of a series of stable switching states that are related to the domain wall motion in the bars. © 2004 American Institute of Physics.
Show PACS
75.30.Et Exchange and superexchange interactions
75.40.Mg Numerical simulation studies
75.50.Bb Fe and its alloys
75.60.Ch Domain walls and domain structure
68.37.Rt Magnetic force microscopy (MFM)

Magnetic and recording properties of Co/Pd islands on prepatterned substrates

G. Hu, T. Thomson, M. Albrecht, M. E. Best, B. D. Terris, C. T. Rettner, S. Raoux, G. M. McClelland, and M. W. Hart

J. Appl. Phys. 95, 7013 (2004); http://dx.doi.org/10.1063/1.1669343 (3 pages) | Cited 24 times

Online Publication Date: 25 May 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Magnetically isolated single domain islands with perpendicular anisotropy have been prepared by depositing Co/Pd multilayer films on prepatterned sub-50 nm SiO2/Si islands. The island arrays were fabricated by both direct write electron beam lithography and nanoimprinting. Nanoimprinting allows the creation of large area, 4 mm×4 mm, samples appropriate for characterization by conventional measurement techniques. Magnetic force microscopy and vibrating sample magnetometry showed that the reversal behavior of the patterned islands is quite different from that of the continuous films with a large increase in both switching field and switching field distribution. Recording on island arrays with a periodicity of 100 nm, produced from prepatterned substrates, was demonstrated using a quasistatic tester. © 2004 American Institute of Physics.
Show PACS
75.70.Cn Magnetic properties of interfaces (multilayers, superlattices, heterostructures)
75.60.Jk Magnetization reversal mechanisms
75.50.Ss Magnetic recording materials
68.65.Ac Multilayers
75.30.Gw Magnetic anisotropy

Domain-specific magnetization reversals on a Permalloy square ring array

D. R. Lee, J. W. Freeland, G. Srajer, V. Metlushko, and Chun-Yeol You

J. Appl. Phys. 95, 7016 (2004); http://dx.doi.org/10.1063/1.1668611 (3 pages) | Cited 3 times

Online Publication Date: 25 May 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We present domain-specific magnetization reversals extracted from soft x-ray resonant magnetic scattering measurements on a Permalloy square ring array. The extracted domain-specific hysteresis loops reveal that the magnetization of the domain parallel to the field is strongly pinned, while those of other domains rotate continuously. In comparison with the micromagnetic simulation, the hysteresis loop on the pinned domain indicates a possibility of the coexistence of the square rings with the vortex and onion states. © 2004 American Institute of Physics.
Show PACS
75.60.Jk Magnetization reversal mechanisms
75.75.-c Magnetic properties of nanostructures
75.25.-j Spin arrangements in magnetically ordered materials (including neutron and spin-polarized electron studies, synchrotron-source x-ray scattering, etc.)

Effect of shape anisotropy on switching behaviors of Pac-man NiFe submicron elements

M. H. Park, Y. K. Hong, S. H. Gee, D. W. Erickson, T. Tanaka, and B. C. Choi

J. Appl. Phys. 95, 7019 (2004); http://dx.doi.org/10.1063/1.1687252 (3 pages) | Cited 9 times

Online Publication Date: 25 May 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We investigated the shape anisotropy effect on switching the behaviors of submicron permalloy Pac-man (PM) elements with a thickness of 40 nm by a magnetic force microscope. The probability to form a vortex configuration at an as-patterned state was lower in an elongated PM type-I (EPM-I) (10%) than a PM-I element (47%). The switching process in PM-I, PM-II, and EPM-I elements was governed by a vortex-driven reversal, while the magnetization of a EPM-II element switches through a single-domain reversal. It was found that a PM element involving a vortex-driven switching process shows a nonreproducible reversal. © 2004 American Institute of Physics.
Show PACS
75.30.Gw Magnetic anisotropy
75.60.Ch Domain walls and domain structure
75.60.Jk Magnetization reversal mechanisms
68.37.Rt Magnetic force microscopy (MFM)

Multidomain and incoherent effects in magnetic nanodots

R. Skomski, A. Kashyap, K. D. Sorge, and D. J. Sellmyer

J. Appl. Phys. 95, 7022 (2004); http://dx.doi.org/10.1063/1.1688645 (3 pages) | Cited 2 times

Online Publication Date: 25 May 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The magnetic ground state and the magnetization reversal of aspherical nanoparticles are investigated by model calculations and micromagnetic simulations. Essential deviations from Kittel’s domain theory occur for very flat and very elongated particles, for particles whose size is comparable to the domain-wall width, and when the particle shape is strongly nonellipsoidal. For example, the single-domain state of square rod is much less stable than that of comparable elongated ellipsoids, because most of the surface charge of long ellipsoids is located on the sides. Another specific feature of flat particles is suppression of the curling mode. © 2004 American Institute of Physics.
Show PACS
75.50.Tt Fine-particle systems; nanocrystalline materials
75.60.Jk Magnetization reversal mechanisms
75.75.-c Magnetic properties of nanostructures

Spin-polarized scanning tunneling spectroscopy study of Fe nanomagnets on W(001)

A. Yamasaki, W. Wulfhekel, R. Hertel, S. Suga, and J. Kirschner

J. Appl. Phys. 95, 7025 (2004); http://dx.doi.org/10.1063/1.1687276 (3 pages)

Online Publication Date: 25 May 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have studied the magnetic states of self-organized Fe islands on W(001) by means of spin-polarized scanning tunneling spectroscopy (Sp-STS). Single-domain and vortex states in the nanoscale islands have been observed. The high-resolution magnetic images enable to experimentally determine the boundary between the single-domain and vortex states. The single-domain state was always found below a thickness of 6 nm and a diameter of 120 nm in Fe islands. The boundary directly observed with Sp-STS is consistent with theoretical predictions. © 2004 American Institute of Physics.
Show PACS
75.70.Ak Magnetic properties of monolayers and thin films
75.50.Tt Fine-particle systems; nanocrystalline materials
75.50.Bb Fe and its alloys
68.37.Ef Scanning tunneling microscopy (including chemistry induced with STM)
68.35.B- Structure of clean surfaces (and surface reconstruction)

Measurement of local magnetization in the buried layer of a pseudo-spin-valve submicron wire

Y. Choi, D. Haskel, D. R. Lee, J. C. Lang, G. Srajer, and J. S. Im

J. Appl. Phys. 95, 7028 (2004); http://dx.doi.org/10.1063/1.1667798 (3 pages)

Online Publication Date: 25 May 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A pseudo-spin-valve (PSV) wire [Au(3 nm)/Py(10 nm)/Cu(5 nm)/Co(10 nm)/Si] was patterned by e-beam lithography into two sections with different widths, connected by a narrow part that acts as a domain wall trap. The two sections have different magnetic shape anisotropies and thus different coercive fields. Since the sample has two different magnetic layers (soft and hard) and two different anisotropies (thick and thin widths), this patterned system has more than two magnetic configuration states depending on the applied field strength. To probe local magnetization from the two different sections, x-ray magnetic circular dichroism (XMCD) measurements were done on the PSV wire with a microfocused x-ray beam. Measurements were done on the buried hard layer, from which magnetic information cannot be obtained by surface-sensitive techniques. The XMCD experimental results are compared with micromagnetic simulations. © 2004 American Institute of Physics.
Show PACS
75.70.Cn Magnetic properties of interfaces (multilayers, superlattices, heterostructures)
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.30.Gw Magnetic anisotropy
75.70.Kw Domain structure (including magnetic bubbles and vortices)

Superparamagnetic transitions in ultrathin film NiFe nanolines

W. Casey Uhlig and Jing Shi

J. Appl. Phys. 95, 7031 (2004); http://dx.doi.org/10.1063/1.1688217 (3 pages) | Cited 2 times

Online Publication Date: 25 May 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We found that the coercivity of electron-beam patterned nanoscale NiFe and Co lines (width ranging from 55 nm to 1 μm) has a distinct inverse-width dependence when the film thickness is greater than 3.5 nm. This inverse-width dependence is consistent with a nucleation picture in which the magnetization reversal is controlled by a small nucleus, which spreads across the width of the nanoline but is independent of the length. However, the inverse-width dependence breaks down for the narrowest NiFe lines at room temperature in films below 3.5 nm in thickness. In this thickness regime the coercivity drops rapidly as a function of decreasing width as the controlling nucleus size approaches the superparamagnetic limit. The Arrhenius–Néel equation for this equivalent volume very effectively models the data. As the temperature is decreased, the coercivity of the narrowest lines rapidly increases and the inverse-width trend is recovered. © 2004 American Institute of Physics.
Show PACS
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.50.Bb Fe and its alloys
68.55.A- Nucleation and growth
75.50.Tt Fine-particle systems; nanocrystalline materials
75.20.En Metals and alloys

High-frequency permalloy permeability extracted from scattering parameters

Pingshan Wang, Weiping Ni, Norman C. Tien, and Edwin C. Kan

J. Appl. Phys. 95, 7034 (2004); http://dx.doi.org/10.1063/1.1668612 (3 pages) | Cited 1 time

Online Publication Date: 25 May 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report a ferromagnetic thin film characterization method and the measured microwave permeability of patterned permalloy films. The method incorporates ferromagnetic materials with transmission lines and extracts RLCG equivalent circuit elements from scattering parameters. The frequency-dependent effective permeability is then obtained from the incremental R and L caused by the ferromagnetic material. The measured high-frequency losses of thin permalloy (Ni80Fe20) films between 1 and 20 GHz show that geometry design restrains ferromagnetic resonance and eddy-current effects effectively. Above ∼22 GHz, mode conversion occurs in the test structures. Other broadband structures are necessary for further extractions. © 2004 American Institute of Physics.
Show PACS
75.50.Bb Fe and its alloys
75.70.Ak Magnetic properties of monolayers and thin films
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
76.50.+g Ferromagnetic, antiferromagnetic, and ferrimagnetic resonances; spin-wave resonance
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close