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

Flickr Twitter iResearch App Facebook

BROWSE VOLUMES

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

23 Jun 2003

Volume 82, Issue 25, pp. 4411-4611

Issue Cover Spotlight Figure

Appl. Phys. Lett. 82, 4322 (2003); http://dx.doi.org/10.1063/1.1582366 (3 pages)

Hongwei Qu, Wei Yao, T. Garcia, Jiandi Zhang, A. V. Sorokin, S. Ducharme, P. A. Dowben, and V. M. Fridkin
Enlarge Image | Read More
Return to All Sections
back to top
RSS Feeds

Magnetic property enhancement of melt-spun Pr2Fe23B3 ribbons with dilute Ti substitution

H. W. Chang, C. H. Chiu, and W. C. Chang

Appl. Phys. Lett. 82, 4513 (2003); http://dx.doi.org/10.1063/1.1584787 (3 pages) | Cited 25 times

Online Publication Date: 16 June 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The phase evolution and magnetic properties of Pr2Fe23B3 and Pr2(Fe0.975Ti0.025)23B3 melt-spun ribbons have been investigated. For Pr2Fe23B3 spun at 25 m/s, the magnetically hard Pr2Fe14B phase coexists with α-Fe, Pr2Fe23B3, and Fe3B when annealed at temperatures above 700 °C, while merely two phases, namely, Pr2Fe14B and α-Fe, coexist if annealed above 800 °C. Because of the excessive annealing, these ribbons exhibit large grain sizes that lead to low Br and iHc values. A slight substitution of Ti for Fe in Pr2(Fe0.975Ti0.025)23B3 suppresses the formation of metastable Pr2Fe23B3 phase and leads to the presence of large amount of Pr2Fe14B and α-Fe phases of fine grain sizes in the matrix even at low annealing temperature (i.e., TH = 650 °C). As a result, the magnetic properties improve remarkably from Br = 6.7 kG, iHc = 1.5 kOe and (BH)max = 1.7 MG Oe of the ternary Pr2Fe23B3 to Br = 9.9 kG, iHc = 5.7 kOe and (BH)max = 15.0 MGOe of the Pr2(Fe0.975Ti0.025)23B3. © 2003 American Institute of Physics.
Show PACS
81.40.Rs Electrical and magnetic properties related to treatment conditions
75.50.Bb Fe and its alloys
75.50.Ww Permanent magnets
81.40.Gh Other heat and thermomechanical treatments
81.20.-n Methods of materials synthesis and materials processing
61.66.Bi Elemental solids
61.66.Dk Alloys

Laser threshold reduction in a spintronic device

J. Rudolph, D. Hägele, H. M. Gibbs, G. Khitrova, and M. Oestreich

Appl. Phys. Lett. 82, 4516 (2003); http://dx.doi.org/10.1063/1.1583145 (3 pages) | Cited 38 times

Online Publication Date: 16 June 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We demonstrate a reduction of the threshold of a semiconductor laser by optically pumping spin-polarized electrons in the gain medium. Polarized electrons couple selectively to one of two possible lasing light modes which effectively reduces the threshold by up to 50% compared to conventional pumping with unpolarized electrons. We theoretically show that our concept can be generalized to an electrically pumped laser. © 2003 American Institute of Physics.
Show PACS
42.55.Px Semiconductor lasers; laser diodes

Strongly coupled critical current density values achieved in Y1Ba2Cu3O7−δ coated conductors with near-single-crystal texture

S. R. Foltyn, P. N. Arendt, Q. X. Jia, H. Wang, J. L. MacManus-Driscoll, S. Kreiskott, R. F. DePaula, L. Stan, J. R. Groves, and P. C. Dowden

Appl. Phys. Lett. 82, 4519 (2003); http://dx.doi.org/10.1063/1.1584783 (3 pages) | Cited 66 times

Online Publication Date: 16 June 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
One of the most intensely researched subjects in the development of YBa2Cu3O7−δ (YBCO)-based coated conductors is the methodology for achieving ever-sharper film texture on flexible metal substrates. This is a critical issue due to the intrinsic weak-link behavior that results in depressed critical current density (Jc) in polycrystalline YBCO. Using ion-beam-assisted deposition of magnesium oxide, we have achieved YBCO texture on superalloy substrates approaching that on single-crystal oxide substrates. This advance has allowed us to fabricate coated conductor samples with Jcs that are as high as for films on oxide crystals; for example, >2 MA/cm2 (75 K, self-field) at a YBCO thickness of ∼1.5 μm. © 2003 American Institute of Physics.
Show PACS
74.25.Sv Critical currents
74.72.-h Cuprate superconductors
74.78.-w Superconducting films and low-dimensional structures

Conducting atomic-force-microscope electrical characterization of submicron magnetic tunnel junctions

D. C. Worledge and David W. Abraham

Appl. Phys. Lett. 82, 4522 (2003); http://dx.doi.org/10.1063/1.1582375 (3 pages) | Cited 21 times

Online Publication Date: 16 June 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have developed the ability to electrically characterize submicron magnetic tunnel junctions using a conducting atomic force microscope (CAFM). This technique can be applied after only a short processing route, thereby saving time and resources, and reducing the potential for damaging the junctions. The CAFM can be used to measure hysteresis loops, magnetoresistance, resistance–area product, switching astroids, current–voltage curves, and breakdown voltage of tunnel junctions. In this letter, we outline the sample requirements, detail the CAFM processing route, describe tip preparation, and report examples of data we have obtained with this technique over the last two years. © 2003 American Institute of Physics.
Show PACS
72.25.Mk Spin transport through interfaces
75.70.Cn Magnetic properties of interfaces (multilayers, superlattices, heterostructures)
68.37.Ps Atomic force microscopy (AFM)
68.35.Ct Interface structure and roughness
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
73.50.Jt Galvanomagnetic and other magnetotransport effects (including thermomagnetic effects)

Microwave intermodulation distortion of MgB2 thin films

G. Lamura, A. J. Purnell, L. F. Cohen, A. Andreone, F. Chiarella, E. Di Gennaro, R. Vaglio, L. Hao, and J. Gallop

Appl. Phys. Lett. 82, 4525 (2003); http://dx.doi.org/10.1063/1.1584519 (3 pages) | Cited 12 times

Online Publication Date: 16 June 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The two-tone intermodulation arising in MgB2 thin films deposited in situ by planar magnetron sputtering on sapphire substrates is studied. Samples are characterized using an open-ended dielectric puck resonator operating at 8.8 GHz. The experimental results show that the third-order products increase with the two-tone input power with a slope ranging between 1.5 and 2.3. The behavior can be understood introducing a mechanism of vortex penetration in grain boundaries as the most plausible source of nonlinearities in these films. This assumption is confirmed by the analysis of the field dependence of the surface resistance, that show a linear behavior at all temperatures under test. © 2003 American Institute of Physics.
Show PACS
74.78.-w Superconducting films and low-dimensional structures
73.25.+i Surface conductivity and carrier phenomena
74.25.N- Response to electromagnetic fields
72.30.+q High-frequency effects; plasma effects
74.25.F- Transport properties
61.72.Mm Grain and twin boundaries

High-resolution detection of resonant frequencies of microwave resonators via magnetic measurements

R. Amigó, J. M. Hernandez, A. García-Santiago, and J. Tejada

Appl. Phys. Lett. 82, 4528 (2003); http://dx.doi.org/10.1063/1.1586786 (3 pages) | Cited 5 times

Online Publication Date: 16 June 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
An experiment with high spin molecular magnets inside microwave resonators has produced the remarkable observation of sharp peaks in the equilibrium magnetization and the ac susceptibility for the resonant frequencies of these devices. These peaks appear when the magnets are pumped or warmed by microwaves to states of different magnetic moment, and allow one to carry out spectroscopic studies of either the magnetic materials or the resonant device. © 2003 American Institute of Physics.
Show PACS
07.55.-w Magnetic instruments and components
75.50.Xx Molecular magnets
75.30.Cr Saturation moments and magnetic susceptibilities
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
84.40.-x Radiowave and microwave (including millimeter wave) technology

Strain-induced charge depletion in La2/3Ca1/3MnO3 epitaxial thin films

S. Valencia, Ll Balcells, J. Fontcuberta, and B. Martínez

Appl. Phys. Lett. 82, 4531 (2003); http://dx.doi.org/10.1063/1.1587000 (3 pages) | Cited 23 times

Online Publication Date: 16 June 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Epitaxial thin films of La2/3Ca1/3MnO3 (LCMO), 50 nm thick, have been grown fully strained, on SrTiO3 (001) substrates. Detailed analyses of the structural and magnetotransport properties, after high-temperature annealing processes, have revealed a progressive increase of the out-of-plane cell parameter c, as the annealing temperature rises but no changes in the in-plane cell parameters are observed. Simultaneously, the magnetic transition temperature, TC, and saturation magnetization, MS, substantially increase. We argue that these results can be described assuming that elastic energy in fully strained films could be minimized by introducing oxygen deficiencies in the as-grown films. This observation provides a simple understanding of the commonly observed depressed magnetotransport properties of LCMO grown on nonmatching substrates. © 2003 American Institute of Physics.
Show PACS
75.47.Lx Magnetic oxides
68.60.Bs Mechanical and acoustical properties
75.50.Dd Nonmetallic ferromagnetic materials
75.70.Ak Magnetic properties of monolayers and thin films
68.55.-a Thin film structure and morphology
61.72.Cc Kinetics of defect formation and annealing
81.40.Gh Other heat and thermomechanical treatments
75.30.Kz Magnetic phase boundaries (including classical and quantum magnetic transitions, metamagnetism, etc.)
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects

Structural and magnetic properties of triode-sputtered epitaxial γ′-Fe4N films deposited on SrTiO3 (001) substrates

K. R. Nikolaev, I. N. Krivorotov, E. D. Dahlberg, V. A. Vas’ko, S. Urazhdin, R. Loloee, and W. P. Pratt

Appl. Phys. Lett. 82, 4534 (2003); http://dx.doi.org/10.1063/1.1586790 (3 pages) | Cited 12 times

Online Publication Date: 16 June 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Highly ordered, single-crystal Fe4N films were prepared on single-crystal SrTiO3 (001) substrates by reactive magnetically enhanced dc triode sputtering. Analytical techniques, including x-ray diffraction, reflectivity, ion channeling, and atomic force microscopy, were used to characterize the structure and morphology of the films. The magnetic properties of the films were measured by magnetic force microscopy and superconducting quantum interference device magnetometry. A technique that utilizes anisotropic magnetoresistance was employed for measurement of the magnetocrystalline anisotropy of the Fe4N films. © 2003 American Institute of Physics.
Show PACS
75.50.Dd Nonmetallic ferromagnetic materials
75.70.Ak Magnetic properties of monolayers and thin films
68.55.-a Thin film structure and morphology
75.30.Gw Magnetic anisotropy
61.85.+p Channeling phenomena (blocking, energy loss, etc.)
68.37.Ps Atomic force microscopy (AFM)
68.37.Rt Magnetic force microscopy (MFM)
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