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

15 May 2003

Volume 93, Issue 10, pp. 5855-8792

Return to All Sections
back to top
RSS Feeds

Electron beam stimulated spin reorientation

T. L. Monchesky, J. Unguris, and R. J. Celotta

J. Appl. Phys. 93, 8241 (2003); http://dx.doi.org/10.1063/1.1556250 (3 pages)

Online Publication Date: 9 May 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Using scanning electron microscopy with polarization analysis, we observed the electron beam induced switching of the magnetic state of epitaxial single-crystal Fe(110) films grown on atomically flat cleaved GaAs(110). For low film thickness the magnetization lies along the [−110] in-plane direction, while above a thickness of 19 monolayers, the ground state magnetization configuration switches to the [001] in-plane direction. If Fe films are grown to a thickness greater than the critical thickness of the reorientation, the magnetization is caught in a metastable state, oriented along [−110]. We discovered that we can locally switch the metastable state to the stable [001] direction by irradiating the metastable magnetic state with a suitable electron current density. The reversal proceeds by the nucleation and growth of lancet-shaped domains that move in discrete jumps between pinning sites. Our results show that there is a permanent reduction of the strength of defect sites without a permanent change in the overall anisotropy. We demonstrate how an electron beam can be used to locally control domain structure.
Show PACS
75.70.Kw Domain structure (including magnetic bubbles and vortices)
75.40.Gb Dynamic properties (dynamic susceptibility, spin waves, spin diffusion, dynamic scaling, etc.)
75.60.Jk Magnetization reversal mechanisms
61.80.Fe Electron and positron radiation effects
75.30.Gw Magnetic anisotropy
61.82.Bg Metals and alloys

Nucleation and evolution of hybrid spin spiral in soft/hard ferromagnetic bilayer

Yu. P. Kabanov, V. S. Gornakov, V. I. Nikitenko, A. J. Shapiro, and R. D. Shull

J. Appl. Phys. 93, 8244 (2003); http://dx.doi.org/10.1063/1.1556134 (3 pages) | Cited 3 times

Online Publication Date: 9 May 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The hybrid exchange spring behavior in a bilayer consisting of an epitaxial film of Fe (500 Å)/Sm2Co7 (350 Å) deposited onto a Cr (200 Å) buffered MgO(110) substrate was investigated using the magneto-optical indicator film technique. Two critical magnitudes of the remagnetizing magnetic field were found that dramatically change the bilayer remanent magnetization. One of them is determined by exchange spring penetration in the interface; another is determined by hybrid spin spiral transformation to domain walls in the hard ferromagnet layer. Unexpected dependence of the direction of average remanent magnetization on the external magnetic field direction and value is revealed. © 2003 American Institute of Physics.
Show PACS
75.70.Cn Magnetic properties of interfaces (multilayers, superlattices, heterostructures)
75.30.Et Exchange and superexchange interactions
75.50.Bb Fe and its alloys
75.50.Cc Other ferromagnetic metals and alloys
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.50.Ww Permanent magnets
78.20.Ls Magneto-optical effects
75.70.Kw Domain structure (including magnetic bubbles and vortices)
78.66.Bz Metals and metallic alloys

Search for noncollinear moments at Permalloy/copper interfaces

Mahesh Vedpathak and R. H. Kodama

J. Appl. Phys. 93, 8247 (2003); http://dx.doi.org/10.1063/1.1556135 (3 pages)

Online Publication Date: 9 May 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Recent first-principles electronic structure calculations have shown a tendency for atomic moments near interfaces between Permalloy (e.g., Ni80Fe20) and Cu to become noncollinear with the bulk magnetization direction. One signature of noncollinear moments should be a differential susceptibility at high fields (i.e., above the nominal saturation field) corresponding to a twisting of the noncollinear moments against the exchange fields in the material. We have measured the differential susceptibility for a series of sputtered Permalloy/Cu multilayers and compared it with the bulk (thick Permalloy) film. We have identified a magnetic contribution due to noncollinear moments at the interfaces corresponding to 0.1–0.3 monolayers. Further, we show that the temperature dependence of the differential susceptibility is not consistent with paramagnetic moments, supporting the idea that exchange-driven noncollinearity is present. © 2003 American Institute of Physics.
Show PACS
75.70.Cn Magnetic properties of interfaces (multilayers, superlattices, heterostructures)
75.30.Cr Saturation moments and magnetic susceptibilities
75.50.Bb Fe and its alloys
75.25.-j Spin arrangements in magnetically ordered materials (including neutron and spin-polarized electron studies, synchrotron-source x-ray scattering, etc.)
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects

Fluctuating spin density waves revealed by perturbed angular correlation spectroscopy

C. L’abbé, J. Meersschaut, M. Rots, and S. D. Bader

J. Appl. Phys. 93, 8250 (2003); http://dx.doi.org/10.1063/1.1558652 (3 pages) | Cited 2 times

Online Publication Date: 9 May 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We present a theory to analyze pertubed angular correlation spectra in the framework of dynamical processes. It can be applied to study superparamagnetic properties of magnetic nanostructures, and was used recently to identify dynamical fluctuations in spin-density-wave ordered Cr. We showed that the spin fluctuations give rise to the biquadratic coupling in Fe/Cr(100) multilayers [J. Meersschaut, C. L’abbé, M. Rots, and S. D. Bader, Phys. Rev. Lett. 87 107201 (2001)]. © 2003 American Institute of Physics.
Show PACS
75.30.Ds Spin waves
75.70.Cn Magnetic properties of interfaces (multilayers, superlattices, heterostructures)
76.80.+y Mössbauer effect; other γ-ray spectroscopy
75.40.Gb Dynamic properties (dynamic susceptibility, spin waves, spin diffusion, dynamic scaling, etc.)
75.50.Tt Fine-particle systems; nanocrystalline materials
75.75.-c Magnetic properties of nanostructures

Micromagnetic behavior of electrodeposited Ni/Cu multilayer nanowires

M. Chen, P. C. Searson, and C. L. Chien

J. Appl. Phys. 93, 8253 (2003); http://dx.doi.org/10.1063/1.1556136 (3 pages) | Cited 12 times

Online Publication Date: 9 May 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Ni/Cu multilayer nanowires have been fabricated by electrodeposition into 6 μm thick nanoporous polycarbonate templates with pore sizes from 30 to 100 nm. The aspect ratio of the magnetic segments was varied from 0.02 (disk shaped) to 50 (rod shaped) with 10–250 Ni/Cu bilayers. The M–H curves show that the magnetic response can be classified in terms of three micromagnetic states depending on the diameter and aspect ratio of the nickel segments. Further, we show that the magnetic behavior is dependent on the thickness of the nonmagnetic layer due to the dipolar interactions between the ferromagnetic segments. © 2003 American Institute of Physics.
Show PACS
75.75.-c Magnetic properties of nanostructures
75.70.Cn Magnetic properties of interfaces (multilayers, superlattices, heterostructures)
75.50.Cc Other ferromagnetic metals and alloys
81.15.Pq Electrodeposition, electroplating
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects

Tunable magnetization reversal in epitaxial bcc Fe1−xCox films on vicinal surfaces

J. A. Wolf, K. K. Anderson, E. D. Dahlberg, P. A. Crowell, L. C. Chen, and C. J. Palmstrøm

J. Appl. Phys. 93, 8256 (2003); http://dx.doi.org/10.1063/1.1556255 (3 pages) | Cited 1 time

Online Publication Date: 9 May 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The magnetic reversal of bcc Fe1−xCox thin films on vicinal Sc1−yEryAs/GaAs(100) is modified by changing the relative strength of the uniaxial and cubic magnetocrystalline anisotropies using substrates with different miscut angles. The surface miscut and applied field geometry are used to induce several changes in the reversal process, which includes up to three first-order jumps. Increasing the miscut angle of the substrate converts one of the easy axes of the cubic anisotropy into a hard axis. When the anisotropy has a local maximum, the first jump in the reversal process occurs at positive magnetic fields. As the angle between the in-plane magnetic field and the hard axis increases, this jump crosses over to continuous rotation. Two-component magneto-optical Kerr effect measurements are used to map out the hysteresis loops, and both components of the magnetization agree qualitatively with the results of a simple coherent rotation model. © 2003 American Institute of Physics.
Show PACS
75.50.Bb Fe and its alloys
75.60.Jk Magnetization reversal mechanisms
75.30.Gw Magnetic anisotropy
75.70.Ak Magnetic properties of monolayers and thin films
78.20.Ls Magneto-optical effects
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close