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

28 Nov 2005

Volume 87, Issue 22, Articles (22xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 87, 221108 (2005); http://dx.doi.org/10.1063/1.2137458 (3 pages)

V. Barna, S. Ferjani, A. De Luca, R. Caputo, N. Scaramuzza, C. Versace, and G. Strangi
Enlarge Image | Read More
Return to All Sections
back to top
RSS Feeds

Rectifying properties of the YBa2Cu3O7−δ/SrTiO3:Nb heterojunction

J. R. Sun, C. M. Xiong, Y. Z. Zhang, and B. G. Shen

Appl. Phys. Lett. 87, 222501 (2005); http://dx.doi.org/10.1063/1.2136407 (3 pages) | Cited 11 times

Online Publication Date: 21 November 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A heterojunction has been fabricated by growing a YBa2Cu3O7−δ (YBCO) film of the thickness of 1000 Å on a 0.5 wt %Nb-doped SrTiO3 (STON) crystal, and its resistive behavior was experimentally studied. The strong asymmetry of the current-voltage (I–V) relation with respect to bias polarity indicates an excellent rectifying property of the junction in the whole temperature range studied. The superconducting transition of YBCO causes a visible reduction of diffusion potential, measured by the forward voltage corresponding to the current rush in the I–V curves, though the general rectifying behavior remains unchanged. This is possibly a result of the variation of the Fermi level of YBCO relative to that of STON, and suggests an alternative technique detecting the effects of superconducting transition in YBCO.
Show PACS
74.78.-w Superconducting films and low-dimensional structures
74.72.-h Cuprate superconductors
73.40.Ei Rectification
74.10.+v Occurrence, potential candidates
74.25.Jb Electronic structure (photoemission, etc.)
74.25.F- Transport properties

Synthesis of high-purity samples of CrO2 by a simple route

A. Bajpai and A. K. Nigam

Appl. Phys. Lett. 87, 222502 (2005); http://dx.doi.org/10.1063/1.2136411 (3 pages) | Cited 18 times

Online Publication Date: 21 November 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Practical applications of the spintronic material CrO2 have been limited, primarily because of the difficulty in its synthesis, as it is not known to form in ambient pressures in a pure form. Here we show that CrO2 can be prepared by a simple route that bypasses the need to either apply any external pressure or measure and control it during synthesis. These samples not only exhibit saturation magnetization (MS) values close to the theoretical predicted one, but also exhibit a substantially enhanced grain size, at least an order of magnitude larger as compared to that reported prior to this work. In addition, the method provides some easy steps to tune the grain size and grain boundary density, thus enabling an investigation of this technologically important material in hitherto unexplored microstructural regimes.
Show PACS
81.05.Bx Metals, semimetals, and alloys
75.50.Cc Other ferromagnetic metals and alloys
61.72.Mm Grain and twin boundaries
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects

Influence of dual-Ru intermediate layers on magnetic properties and recording performance of CoCrPt–SiO2 perpendicular recording media

J. Z. Shi, S. N. Piramanayagam, C. S. Mah, H. B. Zhao, J. M. Zhao, Y. S. Kay, and C. K. Pock

Appl. Phys. Lett. 87, 222503 (2005); http://dx.doi.org/10.1063/1.2137447 (3 pages) | Cited 33 times

Online Publication Date: 22 November 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
CoCrPt–SiO2 perpendicular recording media containing dual-Ru intermediate layers have been studied. The bottom Ru layer deposited under a higher mobility condition, i.e., low Ar gas pressure and bias on substrate, helps to achieve a good crystalline texture, and the top Ru layer under a lower mobility condition, i.e., high Ar gas pressure, promotes the formation of a columnar microstructure. Three kinds of grain boundaries have been observed. The nucleation field and the coercivity as a function of the thickness and dc bias of the bottom Ru layer have been investigated. Medium noise reduction has been observed for dual-Ru intermediate layer media (dual-Ru media) in comparison with that of single intermediate layer media (single-Ru media). This is mainly attributed to the optimization of the physical grain segregation.
Show PACS
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.50.Ss Magnetic recording materials
61.72.Mm Grain and twin boundaries
64.75.-g Phase equilibria

Fe–Ga/Pb(Mg1/3Nb2/3)O3–PbTiO3 magnetoelectric laminate composites

Shuxiang Dong, Junyi Zhai, Naigang Wang, Feiming Bai, JieFang Li, D. Viehland, and T. A. Lograsso

Appl. Phys. Lett. 87, 222504 (2005); http://dx.doi.org/10.1063/1.2137455 (3 pages) | Cited 26 times

Online Publication Date: 22 November 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have found large magnetoelectric (ME) effects in long-type laminate composites of Fe–20%Ga magnetostrictive alloys and piezoelectric Pb(Mg1/3Nb2/3)O3–PbTiO3 single crystals. At lower frequencies, the ME voltage coefficient of a laminate with longitudinally magnetized and longitudinally polarized (i.e., L-L mode) layers was 1.41 V/Oe (or 1.01 V/cm Oe). Near the natural resonant frequency ( ∼ 91 kHz) of the laminate, the ME voltage coefficients were found to be dramatically increased to 50.7 V/Oe (36.2 V/cm Oe) for the L-L mode. In addition, the laminate can detect a minute magnetic field as low as ∼ 2×10−12 T at resonance frequency, and ∼ 1×10−10 T at lower frequencies.
Show PACS
75.80.+q Magnetomechanical effects, magnetostriction
75.50.Bb Fe and its alloys
77.65.-j Piezoelectricity and electromechanical effects
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates

Nanoscale hysteresis loop of individual Co dots by field-dependent magnetic force microscopy

M. V. Rastei, R. Meckenstock, and J. P. Bucher

Appl. Phys. Lett. 87, 222505 (2005); http://dx.doi.org/10.1063/1.2138349 (3 pages) | Cited 6 times

Online Publication Date: 22 November 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We present an approach in which field-dependent magnetic force microscopy (MFM) is used in order to determine the magnetic properties of individual magnetic nanodots. In this work, the integral value of the cantilever phase shift obtained in vibrating MFM experiment is used as a measure of the field dependent magnetization of single objects. The method accounts for details that are resolved at the 10 nm scale, including fine structures during magnetization reversal. Measurements have been done on a model system of embedded dots since the flatness of the free surface reduces strongly the topographic contaminations. It is shown that the method can easily be applied to investigate both out-of-plane and in-plane magnetized dots.
Show PACS
75.50.Tt Fine-particle systems; nanocrystalline materials
75.50.Cc Other ferromagnetic metals and alloys
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.60.Jk Magnetization reversal mechanisms

High-frequency magnetic microstrip local bandpass filters

Bijoy K. Kuanr, D. L. Marvin, T. M. Christensen, R. E. Camley, and Z. Celinski

Appl. Phys. Lett. 87, 222506 (2005); http://dx.doi.org/10.1063/1.2138364 (3 pages) | Cited 30 times

Online Publication Date: 22 November 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
This paper presents results for a compact, local bandpass filter. We fabricated the filter using two different ferromagnetic materials, Fe and NiFe, in a microstrip geometry. The different values of saturation magnetization of the two ferromagnets give rise to different gyromagnetic resonance frequencies and provide a local bandpass region between them. The results show that the center frequency of the filter can be tuned over a wide range by adjusting the magnitude of the bias magnetic field. The filter’s bandwidth is almost constant (3.5±0.5 GHz) over the entire tuning frequency range (6–26 GHz). Theoretical calculations are in good agreement with the experimental results.
Show PACS
84.40.Az Waveguides, transmission lines, striplines
85.70.-w Magnetic devices

Frequency and field dependence of magnetoelectric interactions in layered ferromagnetic transition metal-piezoelectric lead zirconate titanate

V. M. Laletin, N. Paddubnaya, G. Srinivasan, C. P. De Vreugd, M. I. Bichurin, V. M. Petrov, and D. A. Filippov

Appl. Phys. Lett. 87, 222507 (2005); http://dx.doi.org/10.1063/1.2137450 (3 pages) | Cited 32 times

Online Publication Date: 23 November 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The strength of magnetoelectric (ME) coupling at 10 Hz–3 MHz has been measured in trilayers of Fe, Co, or Ni and lead zirconate titanate (PZT). The strongest ME coupling is measured for trilayers with Ni and the weakest in Co. Data on ME voltage coefficient αE versus bias magnetic field H for Fe–PZT–Fe show unique features including zero crossing and sign reversal. Measurements of frequency dependence of αE reveal a giant ME coupling due to the electromechanical resonance at 200–300 kHz for radial modes and at ∼ 2.7 MHz for thickness modes. Theoretical estimates of field and frequency dependence of αE are in very good agreement with the data.
Show PACS
75.80.+q Magnetomechanical effects, magnetostriction
75.50.Bb Fe and its alloys
75.50.Cc Other ferromagnetic metals and alloys
77.65.-j Piezoelectricity and electromechanical effects
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
75.70.Cn Magnetic properties of interfaces (multilayers, superlattices, heterostructures)
75.30.Kz Magnetic phase boundaries (including classical and quantum magnetic transitions, metamagnetism, etc.)

Giant tunneling magnetoresistance in fully epitaxial body-centered-cubic Co/MgO/Fe magnetic tunnel junctions

Shinji Yuasa, Toshikazu Katayama, Taro Nagahama, Akio Fukushima, Hitoshi Kubota, Yoshishige Suzuki, and Koji Ando

Appl. Phys. Lett. 87, 222508 (2005); http://dx.doi.org/10.1063/1.2138355 (3 pages) | Cited 41 times

Online Publication Date: 23 November 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Fully epitaxial bcc Fe1−xCox(001)/MgO(001)/Fe(001) magnetic tunnel junctions (x = 0, 0.5, 1) were fabricated with molecular-beam epitaxy and microfabrication techniques. While the bcc Fe(001) and Fe0.5Co0.5(001) electrodes had similar magnetoresistance (MR) ratios of about 180% at room temperature, the bcc Co(001) electrode exhibited a higher MR ratio up to 271% at room temperature (353% at 20 K). The fact that the MR ratio for a bcc Co electrode is much higher than that for a bcc Fe electrode is consistent with first-principle calculations, indicating the importance of electrode band structure in the k‖ = 0 direction.
Show PACS
75.50.Bb Fe and its alloys
75.47.De Giant magnetoresistance
75.70.Cn Magnetic properties of interfaces (multilayers, superlattices, heterostructures)
71.15.-m Methods of electronic structure calculations
71.20.Ps Other inorganic compounds

Bidomain state in exchange biased FeF2/Ni

O. Petracic, Zhi-Pan Li, Igor V. Roshchin, M. Viret, R. Morales, X. Batlle, and Ivan K. Schuller

Appl. Phys. Lett. 87, 222509 (2005); http://dx.doi.org/10.1063/1.2138357 (3 pages) | Cited 24 times

Online Publication Date: 23 November 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Independently exchange biased subsystems can coexist in ferromagnet/antiferromagnet bilayers after various field-cooling protocols. We find well separated double hysteresis loops in FeF2/Ni bilayers for intermediate cooling fields, while for small or large cooling fields a negatively or positively shifted single loop, respectively, are encountered. The antiferromagnet breaks into a bidomain state with opposite signs but equal magnitude of bias acting on the ferromagnet. This idea is supported by micromagnetic simulations. Experiments are presented, where thermally activated motion of these antiferromagnetic domain boundaries can be achieved.
Show PACS
75.70.Cn Magnetic properties of interfaces (multilayers, superlattices, heterostructures)
75.60.Ch Domain walls and domain structure
75.70.Kw Domain structure (including magnetic bubbles and vortices)
75.50.Dd Nonmetallic ferromagnetic materials
75.50.Ee Antiferromagnetics
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.30.Et Exchange and superexchange interactions

Spin transfer switching current reduction in magnetic tunnel junction based dual spin filter structures

Yiming Huai, Mahendra Pakala, Zhitao Diao, and Yunfei Ding

Appl. Phys. Lett. 87, 222510 (2005); http://dx.doi.org/10.1063/1.2138363 (3 pages) | Cited 27 times

Online Publication Date: 23 November 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Spin-transfer-driven magnetization switching was studied in single magnetic tunneling junctions (MTJ: Ta/PtMn/CoFe/Ru/CoFeB/Al2O3/CoFeB/Ta) and dual spin filters (DSF: Ta/PtMn/CoFe/Ru/CoFeB/Al2O3/CoFeB/spacer/CoFe/PtMn/Ta) having resistance-area (RA) product in the range of 10–30 Ω μm2 and tunnel magnetoresistance (TMR) of 15%–30%. The intrinsic critical current density (Jc0) was estimated by extrapolating experimentally obtained critical current density (Jc) versus pulse width (τ) data to a pulse width of 1 ns. Jc, extrapolated to τ of 1 ns ( ∼ Jc0), was 7×106 and 2.2×106 A/cm2, respectively, for the MTJ and improved DSF samples having identical free layers. Thus, a significant enhancement of the spin transfer switching efficiency is seen for DSF structures compared to the single MTJ case.
Show PACS
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.47.Pq Other materials
85.75.-d Magnetoelectronics; spintronics: devices exploiting spin polarized transport or integrated magnetic fields

Josephson junctions with nearly superconducting metal silicide barriers

Yonuk Chong, N. Hadacek, P. D. Dresselhaus, C. J. Burroughs, B. Baek, and S. P. Benz

Appl. Phys. Lett. 87, 222511 (2005); http://dx.doi.org/10.1063/1.2137992 (3 pages) | Cited 8 times

Online Publication Date: 23 November 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We present a detailed study of the electrical properties of Nb-based planar Josephson junctions with superconducting metal silicide barriers, TiSi2 and WSi2. While these nonhysteretic junctions are useful for voltage standard applications, they are also an excellent model system to study proximity coupling in junctions having a barrier with a finite superconducting transition temperature. These silicide-barrier junctions have excellent uniformity and controllability, but as opposed to junction barriers with no measurable superconducting transition, the critical current of these superconducting-barrier junctions is a strong function of the operating temperature near 4 K; we also discuss the impact of this temperature dependence on device applications.
Show PACS
74.25.F- Transport properties
74.50.+r Tunneling phenomena; Josephson effects
74.10.+v Occurrence, potential candidates
74.25.Sv Critical currents
74.70.Ad Metals; alloys and binary compounds (including A15, MgB2, etc.)
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close