APL Nameplate
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Flickr Twitter iResearch App Facebook

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Previous Issue

28 Jun 1999

Volume 74, Issue 26, pp. 3921-4070

Return to All Sections
back to top
RSS Feeds

Variable sample temperature scanning superconducting quantum interference device microscope

J. R. Kirtley, C. C. Tsuei, K. A. Moler, V. G. Kogan, J. R. Clem, and A. J. Turberfield

Appl. Phys. Lett. 74, 4011 (1999); http://dx.doi.org/10.1063/1.123244 (3 pages) | Cited 25 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We demonstrate a design for a scanning superconducting quantum interference device (SQUID) microscope in which the sample temperature can be varied over a large range. In this design, both sample and SQUID are in the same vacuum space, separated by a few microns. By firmly anchoring the SQUID to a low-temperature bath, the sample temperature can be changed while the SQUID remains superconducting. This allows magnetic imaging at varying sample temperatures with micron-scale spatial resolution and the sensitivity of a low-Tc SQUID. We demonstrate this approach by imaging the temperature dependence of Abrikosov vortices in thin films of the high-temperature superconductor YBa2Cu3O7−δ. We extract the in-plane penetration depth λab(T) in our samples from these measurements. © 1999 American Institute of Physics.
Show PACS
07.55.Ge Magnetometers for magnetic field measurements
85.25.Dq Superconducting quantum interference devices (SQUIDs)
74.72.-h Cuprate superconductors
74.78.-w Superconducting films and low-dimensional structures
74.25.Ha Magnetic properties including vortex structures and related phenomena
74.25.Uv Vortex phases (includes vortex lattices, vortex liquids, and vortex glasses)

Enhanced field sensitivity close to percolation in magnetoresistive La2/3Sr1/3MnO3/CeO2 composites

Ll. Balcells, A. E. Carrillo, B. Martínez, and J. Fontcuberta

Appl. Phys. Lett. 74, 4014 (1999); http://dx.doi.org/10.1063/1.123245 (3 pages) | Cited 128 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The magnetoresistance of La2/3Sr1/3MnO3/CeO2 composites is explored as a function of the metal/insulator composition, temperature, and magnetic field. An important enhancement of the low-field magnetoresistance is observed for samples close to metallic percolation threshold. The improved field sensitivity is still fairly large at room temperature. Manganese perovskites composites may constitute a new alternative for the development of magnetoresistive devices. © 1999 American Institute of Physics.
Show PACS
75.47.Gk Colossal magnetoresistance
75.50.Dd Nonmetallic ferromagnetic materials

Large magnetoresistance in tunnel junctions with an iron oxide electrode

P. Seneor, A. Fert, J.-L. Maurice, F. Montaigne, F. Petroff, and A. Vaurès

Appl. Phys. Lett. 74, 4017 (1999); http://dx.doi.org/10.1063/1.123246 (3 pages) | Cited 80 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report on the fabrication and properties of (cobalt/alumina/iron oxide) tunnel junctions. We observe magnetoresistance (MR) effects reaching 43% at 4.2 K and 13% at room temperature. This large MR is ascribed to the presence of a Fe3−xO4 (close to half-metallic magnetite) phase identified by electron diffraction. At low temperature, the MR drops sharply when the bias voltage is smaller than 10 mV, which suggests that the magnetoresistance originates from the activation of tunneling channels through spin polarized states below and above the Fermi level in the iron oxide. © 1999 American Institute of Physics.
Show PACS
73.40.Ns Metal-nonmetal contacts
73.40.Gk Tunneling

Structure and magnetic properties of Gd3(Fe1−xCox)25Cr4 compounds

Dong Yang, Jianli Wang, Ning Tang, Yuping Shen, and Fuming Yang

Appl. Phys. Lett. 74, 4020 (1999); http://dx.doi.org/10.1063/1.123247 (3 pages) | Cited 14 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The structural and magnetic properties of Gd3(Fe1−xCox)25Cr4 compounds with x = 0–0.6 have been investigated. The structures of all the compounds investigated are found to possess monoclinic symmetry and belong to the A2/m space group. Substitution of Co for Fe leads to a clear contraction of the unit-cell volume. The Curie temperature increases from 492 K for x = 0 to 762 K for x = 0.6. The composition dependence of the saturation magnetization at 5 K reaches a maximum around x = 0.3. It is noteworthy that substitution of Co for Fe results in a significant change of the magnetocrystalline anisotropy of the Co sublattice, and changes the easy magnetization direction of Gd3(Fe1−xCox)25Cr4 compounds from basal plane to easy axis. © 1999 American Institute of Physics.
Show PACS
75.50.Ww Permanent magnets
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.30.Gw Magnetic anisotropy
61.05.cp X-ray diffraction

Nonlinear inductive response of high temperature superconducting films measured by the mutual inductance technique

J. H. Claassen, James C. Booth, J. A. Beall, D. A. Rudman, L. R. Vale, and R. H. Ono

Appl. Phys. Lett. 74, 4023 (1999); http://dx.doi.org/10.1063/1.123248 (3 pages) | Cited 11 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The dependence of the penetration depth λ on current density J in an unpatterned superconducting film can be measured with a pair of small coaxial coils positioned on opposite sides of the film. Mutual inductance measurements in this configuration with a direct-current (dc) current component in one of the coils provide a means to determine λ(J). It is possible to separate out the effects of heating by initially trapping a persistent current in the film. The nonlinear (current-dependent) coefficients of λ(J) measured by this “dc” technique agree well with those measured by third harmonic generation in coplanar waveguide transmission lines at 5 GHz. This nondestructure technique could be used to screen films before incorporating them into circuits sensitive to nonlinear effects.
Show PACS
74.78.-w Superconducting films and low-dimensional structures
74.72.-h Cuprate superconductors
74.25.N- Response to electromagnetic fields

Magnetoresistance and planar Hall effects in submicron exchange-coupled NiO/Fe19Ni81 wires

A. Nemoto, Y. Otani, S. G. Kim, K. Fukamichi, O. Kitakami, and Y. Shimada

Appl. Phys. Lett. 74, 4026 (1999); http://dx.doi.org/10.1063/1.123249 (3 pages) | Cited 25 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Magnetization reversal processes of submicron NiO/Fe19Ni81 exchange-coupled Hall cross with a variable width in the range from 0.2 to 0.4 μm were studied by the magnetoresistivity and the planar Hall effect measurements. The magnetization reversal was found to take place via a coherent rotation in the Hall cross, suggesting that the size of the antiferromagnetic domain is regulated by the wire width. The magnitude of the exchange coupling field Hex varied in proportion to the inverse wire width. © 1999 American Institute of Physics.
Show PACS
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
73.50.Jt Galvanomagnetic and other magnetotransport effects (including thermomagnetic effects)
75.30.Et Exchange and superexchange interactions
75.60.Ch Domain walls and domain structure
75.50.Ee Antiferromagnetics
73.61.-r Electrical properties of specific thin films
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close