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

30 Jan 2012

Volume 100, Issue 5, Articles (05xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 100, 053101 (2012); http://dx.doi.org/10.1063/1.3679127 (3 pages)

Shinya Kano, Yasuyuki Yamada, Kentaro Tanaka, and Yutaka Majima
Enlarge Image | Read More
Page 2 of 5 Pages Previous Page Next Page | Jump to Page
back to top
RSS Feeds

Quantum Hall effect in bottom-gated epitaxial graphene grown on the C-face of SiC

B. Jouault, N. Camara, B. Jabakhanji, A. Caboni, C. Consejo, P. Godignon, D. K. Maude, and J. Camassel

Appl. Phys. Lett. 100, 052102 (2012); http://dx.doi.org/10.1063/1.3680564 (4 pages) | Cited 2 times

Online Publication Date: 30 January 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We demonstrate that the carrier concentration of epitaxial graphene devices grown on the C-face of a SiC substrate is efficiently modulated by a buried gate. The gate is fabricated via the implantation of nitrogen atoms in the SiC crystal. The charge neutrality point is observed close to gate voltage zero, and graphene can be populated by either holes or electrons down to low temperature (1.5 K). The hole concentration is hardly tuned by the gate voltage, possibly because of interface states below the Dirac point. A remarkably large quantum Hall plateau is observed for electrons.
Show PACS
73.43.-f Quantum Hall effects
73.61.Wp Fullerenes and related materials

Influence of charge compensation mechanisms on the sheet electron density at conducting LaAlO3/SrTiO3-interfaces

F. Gunkel, P. Brinks, S. Hoffmann-Eifert, R. Dittmann, M. Huijben, J. E. Kleibeuker, G. Koster, G. Rijnders, and R. Waser

Appl. Phys. Lett. 100, 052103 (2012); http://dx.doi.org/10.1063/1.3679139 (3 pages) | Cited 2 times

Online Publication Date: 30 January 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The equilibrium conductance of LaAlO3/SrTiO3 (LAO/STO)-heterointerfaces was investigated at high temperatures (950 K-1100 K) as a function of ambient oxygen partial pressure (pO2). Metallic LAO/STO-interfaces were obtained for LAO grown on STO single crystals as well as on STO-buffered (La,Sr)(Al,Ta)O3 substrates. For both structures, the high temperature sheet carrier density nS of the LAO/STO-interface saturates at a value of about 1 × 1014 cm−2 for reducing conditions, which indicates the presence of interfacial donor states. A significant decrease of nS is observed at high oxygen partial pressures. According to the defect chemistry model of donor-doped STO, this behavior for oxidizing conditions can be attributed to the formation of Sr-vacancies as charge compensating defects.
Show PACS
73.40.-c Electronic transport in interface structures
61.72.jd Vacancies
71.55.Ht Other nonmetals
72.80.Sk Insulators

Effect of electric field on the band structure of graphene/boron nitride and boron nitride/boron nitride bilayers

Radhakrishnan Balu, Xiaoliang Zhong, Ravindra Pandey, and Shashi P. Karna

Appl. Phys. Lett. 100, 052104 (2012); http://dx.doi.org/10.1063/1.3679174 (3 pages) | Cited 7 times

Online Publication Date: 30 January 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Effect of electric field on the band structures of graphene/boron nitride (BN) and BN/BN bilayers is investigated within the framework of density functional theory. The calculated bandgap of the graphene/BN bilayer increases, although by small amount, with applied electric field. In the case of BN/BN bilayer, the bandgap decreases with the applied field in agreement with earlier studies. The modulation of bandgap in graphene/BN bilayers is dominated by the features of graphene and appears to be related to the modification in molecular orbitals as revealed by the calculated projected density of states.
Show PACS
71.20.Nr Semiconductor compounds
71.15.Mb Density functional theory, local density approximation, gradient and other corrections

Pseudobinary Al2Te3-Sb2Te3 material for high speed phase change memory application

Kun Ren, Feng Rao, Zhitang Song, Shilong Lv, Yan Cheng, Liangcai Wu, Cheng Peng, Xilin Zhou, Mengjiao Xia, Bo Liu, and Songlin Feng

Appl. Phys. Lett. 100, 052105 (2012); http://dx.doi.org/10.1063/1.3680580 (3 pages) | Cited 3 times

Online Publication Date: 31 January 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Al2Sb2Te6 is a pseudobinary material constructed by Sb2Te3 (fast crystallization speed but thermally unstable) and Al2Te3 (thermally stable but without memory switching ability). Al2Sb2Te6 material possesses advantages of these two binary compounds showing good memory switching ability with fast switching speed and good thermal stability. These improvements are believed to be closely related to the coordination situations of Al atoms in Al2Sb2Te6 material. Phase change memory device using Al2Sb2Te6 showed high speed (∼5 ns), low power consumption, and high endurance (∼106 cycles). Thus, we consider that Al2Sb2Te6 can be one of the most promising materials for phase change memory use.
Show PACS
84.30.Sk Pulse and digital circuits
68.60.Dv Thermal stability; thermal effects

Epitaxial Cr on n-SrTiO3(001)—An ideal Ohmic contact

C. Capan, G. Y. Sun, M. E. Bowden, and S. A. Chambers

Appl. Phys. Lett. 100, 052106 (2012); http://dx.doi.org/10.1063/1.3680608 (3 pages) | Cited 1 time

Online Publication Date: 31 January 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Epitaxial Cr metallizations grown on n-SrTiO3(001) by molecular beam epitaxy are shown to result in an ordered interface with Cr bound to O in the terminal TiO2 layer, no reduction of the SrTiO3, and a near-perfect Ohmic contact. Cr/n-SrTiO3(001) thus constitutes an ideal interface between a pure metal and wide gap oxide in which interface redox chemistry does not occur, and the Fermi level remains unpinned.
Show PACS
73.40.Ns Metal-nonmetal contacts
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy

2-bit operation based on modulated Fowler-Nordheim tunneling in charge-trapping flash memory cell

Min-Feng Hung, Yung-Chun Wu, and Jiang-Hung Chen

Appl. Phys. Lett. 100, 052107 (2012); http://dx.doi.org/10.1063/1.3681145 (3 pages)

Online Publication Date: 31 January 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
This work proposes a spatially charge tunneling method for program/erase (P/E) based on the drain-modulated Fowler-Nordheim (MFN) tunneling in a polycrystalline silicon channel charge-trap type flash memory device. The program mechanism and the simulation of the MFN are discussed. 2-bit operations based on MFN and channel hot electron injection were demonstrated. MFN 2-bit operation and conventional 2-bit operation present different transfer curves, indicating that charge is injected into the different regions. The MFN P/E operation provides flexibility in flash memory applications.
Show PACS
85.30.-z Semiconductor devices
84.30.Sk Pulse and digital circuits

Growth and valence band offset measurement of PbTe/InSb heterojunctions

Kyoung-Keun Lee, Weerasinghe Priyantha, and Thomas H. Myers

Appl. Phys. Lett. 100, 052108 (2012); http://dx.doi.org/10.1063/1.3681161 (4 pages) | Cited 2 times

Online Publication Date: 31 January 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
InSb (111)B and (211)B substrates were investigated for the growth of PbTe. The PbTe/InSb (111)B showed slip features caused by stain relaxation during cooling down, while growth of PbTe/InSb (211)B resulted in a better surface morphology. The valence band offset of PbTe/InSb (211)B was measured by high resolution x-ray photoemission spectroscopy and ultraviolet photoemission spectroscopy with the value of 0.38 ± 0.05 eV. The PbTe/InSb (211)B heterojunction structure forms a type-III—broken gap heterostructure with the conduction band offset of 0.23 ± 0.05 eV.
Show PACS
71.20.Nr Semiconductor compounds
79.60.Bm Clean metal, semiconductor, and insulator surfaces
82.80.Pv Electron spectroscopy (X-ray photoelectron (XPS), Auger electron spectroscopy (AES), etc.)
68.35.bg Semiconductors

Boundary-enhanced momentum relaxation of longitudinal optical phonons in GaN

N. Ma, B. Shen, L. W. Lu, F. J. Xu, L. Guo, X. Q. Wang, F. Lin, Z. H. Feng, S. B. Dun, and B. Liu

Appl. Phys. Lett. 100, 052109 (2012); http://dx.doi.org/10.1063/1.3681373 (3 pages)

Online Publication Date: 1 February 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The influence of the channel geometry on the high-field electron transport properties has been investigated in n-type GaN at room temperature. It is found that electrons in narrow channels drift much faster than those in wide channels. This discrepancy is attributed to the boundary-enhanced momentum relaxation of longitudinal optical (LO) phonons, which increases the electron drift velocity through enhancing the electron energy dissipation while weakening the momentum relaxation. In narrow channels, the effective LO-phonon momentum relaxation time is about ∼0.67 ps. The suggested theoretical analysis coincides well with the important features of the experimental results.
Show PACS
63.20.D- Phonon states and bands, normal modes, and phonon dispersion
68.55.ag Semiconductors
73.61.Ey III-V semiconductors
81.05.Ea III-V semiconductors
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)

Modeling the transport properties of epitaxially grown thermoelectric oxide thin films using spectroscopic ellipsometry

S. R. Sarath Kumar, Anas I. Abutaha, M. N. Hedhili, and H. N. Alshareef

Appl. Phys. Lett. 100, 052110 (2012); http://dx.doi.org/10.1063/1.3678186 (4 pages)

Online Publication Date: 1 February 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The influence of oxygen vacancies on the transport properties of epitaxial thermoelectric (Sr,La)TiO3 thin films is determined using electrical and spectroscopic ellipsometry (SE) measurements. Oxygen vacancy concentration was varied by ex-situ annealing in Ar and Ar/H2. All films exhibited degenerate semiconducting behavior, and electrical conductivity decreased (258–133 S cm−1) with increasing oxygen content. Similar decrease in the Seebeck coefficient is observed and attributed to a decrease in effective mass (7.8–3.2 me), as determined by SE. Excellent agreement between transport properties deduced from SE and direct electrical measurements suggests that SE is an effective tool for studying oxide thin film thermoelectrics.
Show PACS
73.50.Lw Thermoelectric effects
73.61.Le Other inorganic semiconductors
61.72.jd Vacancies
68.55.ag Semiconductors
61.72.Cc Kinetics of defect formation and annealing
72.20.Pa Thermoelectric and thermomagnetic effects

Electronic transport anisotropy of buckling graphene under uniaxial compressive strain: Ab initio study

Yang Xu, Haiyuan Gao, Huabin Chen, You Yuan, Kaicheng Zhu, Hongsheng Chen, Zhonghe Jin, and Bin Yu

Appl. Phys. Lett. 100, 052111 (2012); http://dx.doi.org/10.1063/1.3680092 (3 pages) | Cited 1 time

Online Publication Date: 1 February 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Electronic transport properties of graphene under uniaxial compressive strain are studied using ab initio calculations. With approximate thermal perturbation, buckling occurs when strain exceeds a threshold, comparing to flat unperturbed structures. Transmissions of flat graphene compressed along zigzag direction (ZCG) and buckled graphene compressed along armchair direction (ACG) are insensitive to strain, whereas those of buckled ZCG and flat ACG are negatively correlated to strain. Flat graphene has anisotropic resistance along the strain direction, while buckling suppresses the anisotropy by releasing the strain. The insensitivity of buckled graphene on strain direction and out-of-plane deformation makes feasible to implement flexible electronics.
Show PACS
81.40.Lm Deformation, plasticity, and creep
62.20.mq Buckling

Negative differential spin conductance in doped zigzag graphene nanoribbons

Ting-Ting Wu, Xue-Feng Wang, Ming-Xing Zhai, Hua Liu, Liping Zhou, and Yong-Jin Jiang

Appl. Phys. Lett. 100, 052112 (2012); http://dx.doi.org/10.1063/1.3681775 (4 pages) | Cited 2 times

Online Publication Date: 2 February 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The spin dependent charge transport in zigzag graphene nanoribbons (ZGNRs) has been investigated by the nonequilibrium Green’s function method combined with the density functional theory at the local spin density approximation. The current versus voltage curve shows distinguished behaviors for symmetric and asymmetric ZGNRs, and the doping on the ZGNR edges can manipulate the spin transport. In special cases that a Be atom is substitutionally doped on one edge of the symmetric ZGNRs, one spin current shows negative differential resistance, whereas the other increases monotonically with the bias. This property might be used to design spin oscillators or other devices for spintronics.
Show PACS
72.25.-b Spin polarized transport
72.80.Vp Electronic transport in graphene
72.20.Ht High-field and nonlinear effects

The effect of growth temperature of GaAs nucleation layer on InAs/GaAs quantum dots monolithically grown on Ge substrates

T. Wang, A. Lee, F. Tutu, A. Seeds, H. Liu, Q. Jiang, K. Groom, and R. Hogg

Appl. Phys. Lett. 100, 052113 (2012); http://dx.doi.org/10.1063/1.3682314 (4 pages) | Cited 2 times

Online Publication Date: 2 February 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The effect of the growth temperature of the GaAs nucleation layer on the properties of 1.3-μm InAs/GaAs quantum dots (QDs) monolithically grown on a Ge substrate is investigated by using transmission electron microscopy, etch pit density, and photoluminescence (PL) measurements. The photoluminescence intensity for Ge-based InAs/GaAs quantum dots is very sensitive to the initial GaAs nucleation temperature with the strongest room-temperature emission at 380 °C, due to the lower density of defects generated at the GaAs/Ge interface and prorogating into the III-V layers at this temperature. Furthermore, lasing operation up to 100 °C was achieved for Ge-based 1.3-μm InAs/GaAs quantum-dot diodes with the initial GaAs layer nucleated at 380 °C.
Show PACS
81.07.Ta Quantum dots
78.67.Hc Quantum dots
42.55.Px Semiconductor lasers; laser diodes
71.55.Eq III-V semiconductors
78.55.Cr III-V semiconductors
81.05.Ea III-V semiconductors

Deep traps in nonpolar m-plane GaN grown by ammonia-based molecular beam epitaxy

Z. Zhang, C. A. Hurni, A. R. Arehart, J. Yang, R. C. Myers, J. S. Speck, and S. A. Ringel

Appl. Phys. Lett. 100, 052114 (2012); http://dx.doi.org/10.1063/1.3682528 (4 pages) | Cited 1 time

Online Publication Date: 3 February 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Deep level defects in nonpolar m-plane GaN grown by ammonia-based molecular beam epitaxy were characterized using deep level transient spectroscopy (DLTS) and deep level optical spectroscopy (DLOS) and compared with polar c-plane GaN that was grown simultaneously in the same growth run. Significant differences in both the levels present and their concentrations were observed upon comparison of both growth orientations. DLTS revealed electron traps with activation energies of 0.14 eV, 0.20 eV, and 0.66 eV in the m-plane material, with concentrations that were ∼10−50 × higher than traps of similar activation energies in the c-plane material. Likewise, DLOS measurements showed ∼20 × higher concentrations of both a CN acceptor-like state at EC − 3.26 eV, which correlates with a high background carbon concentration observed by secondary ion mass spectroscopy for the m-plane material [A. Armstrong, A. R. Arehart, B. Moran, S. P. DenBaars, U. K. Mishra, J. S. Speck, and S. A. Ringel, Appl. Phys. Lett. 84, 374 (2004)], and the VGa-related state level at EC − 2.49 eV, which is consistent with an enhanced yellow luminescence observed by photoluminescence. The findings suggest a strong impact of growth dynamics on the incorporation of impurities and electrically active native point defects as a function of GaN growth plane polarity.
Show PACS
71.55.Eq III-V semiconductors
78.55.Cr III-V semiconductors
78.66.Fd III-V semiconductors
81.05.Ea III-V semiconductors
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy

Role of deep and shallow donor levels on n-type conductivity of hydrothermal ZnO

S. Brochen, C. Granier, G. Feuillet, and J. Pernot

Appl. Phys. Lett. 100, 052115 (2012); http://dx.doi.org/10.1063/1.3681168 (4 pages) | Cited 2 times

Online Publication Date: 3 February 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The residual n-type conductivity of O-polar hydrothermally grown ZnO single crystals and the role of annealing on the transport properties are assessed by temperature dependent Hall measurements on a wide 20–800 K temperature range. A deep level lying 250 meV below the conduction band is responsible for the residual n-type conductivity of unannealed samples. After annealing, a shallow donor level with 25 meV ionization energy becomes responsible for the sample conductivity in the room temperature range. Thanks to high temperature Hall measurement, the coexistence of the deep and the shallow level has been demonstrated in the case of annealed sample.
Show PACS
72.20.Fr Low-field transport and mobility; piezoresistance
72.20.My Galvanomagnetic and other magnetotransport effects
72.80.Ey III-V and II-VI semiconductors
73.20.At Surface states, band structure, electron density of states
61.72.Cc Kinetics of defect formation and annealing
71.55.Gs II-VI semiconductors
back to top
RSS Feeds

Itinerant ferromagnetism and geometrically suppressed metal-insulator transition in epitaxial thin films of Ca2RuO4

Ludi Miao, Punam Silwal, Xiaolan Zhou, Ilan Stern, Jin Peng, Wenyong Zhang, Leonard Spinu, Zhiqiang Mao, and Dae Ho Kim

Appl. Phys. Lett. 100, 052401 (2012); http://dx.doi.org/10.1063/1.3680250 (3 pages) | Cited 1 time

Online Publication Date: 31 January 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have investigated the effect of epitaxial strain on the electrical and magnetic properties of high quality Ca2RuO4 films on LaAlO3 (001) substrates. The films exhibit low temperature itinerant ferromagnetic ground state and significantly suppressed metal-insulator transition due to epitaxial strain. An anomaly in the in-plane resistivity was also observed near the Néel temperature. Symmetry analysis of anisotropic magnetoresistance suggests a phase coexistence of ferromagnetic metal and antiferromagnetic insulator in ground state.
Show PACS
73.61.Ng Insulators
75.50.Dd Nonmetallic ferromagnetic materials
72.20.My Galvanomagnetic and other magnetotransport effects
73.50.Jt Galvanomagnetic and other magnetotransport effects (including thermomagnetic effects)
71.30.+h Metal-insulator transitions and other electronic transitions
75.70.Ak Magnetic properties of monolayers and thin films

Fabrication and magnetic properties of free-standing Ni nanotube arrays with controllable wall thickness

Y. L. Li, S. L. Tang, R. Xie, Y. Wang, M. Yang, J. L. Gao, W. B. Xia, and Y. W. Du

Appl. Phys. Lett. 100, 052402 (2012); http://dx.doi.org/10.1063/1.3681136 (3 pages) | Cited 2 times

Online Publication Date: 31 January 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Free-standing Ni nanotubes were fabricated on silicon substrate using anodic aluminum oxide/polypyrrole composite template. The diameter, length, and wall thickness of the nanotubes can be precisely and independently controlled. Magnetic measurements show that the magnetic anisotropic properties are strongly dependent on the wall thickness of nanotubes. Theoretical analysis and micromagnetic simulation were performed to explain the wall thickness-dependent anisotropic behavior.
Show PACS
75.75.Cd Fabrication of magnetic nanostructures
75.30.Gw Magnetic anisotropy
75.50.Cc Other ferromagnetic metals and alloys
81.07.De Nanotubes

Influence of a transverse static magnetic field on the magnetic hyperthermia properties and high-frequency hysteresis loops of ferromagnetic FeCo nanoparticles

B. Mehdaoui, J. Carrey, M. Stadler, A. Cornejo, C. Nayral, F. Delpech, B. Chaudret, and M. Respaud

Appl. Phys. Lett. 100, 052403 (2012); http://dx.doi.org/10.1063/1.3681361 (3 pages) | Cited 9 times

Online Publication Date: 1 February 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The influence of a transverse static magnetic field on the magnetic hyperthermia properties is studied on a system of large-losses ferromagnetic FeCo nanoparticles. The simultaneous measurement of the high-frequency hysteresis loops and of the temperature rise provides an interesting insight into the losses and heating mechanisms. A static magnetic field of only 40 mT is enough to cancel the heating properties of the nanoparticles, a result reproduced using numerical simulations of hysteresis loops. These results cast doubt on the possibility to perform someday magnetic hyperthermia inside a magnetic resonance imaging setup.
Show PACS
87.19.Pp Biothermics and thermal processes in biology
87.61.-c Magnetic resonance imaging
75.75.-c Magnetic properties of nanostructures
72.30.+q High-frequency effects; plasma effects
75.50.Bb Fe and its alloys
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects

Magnetostructural phase transitions and magnetocaloric effects in MnNiGe1−xAlx

Tapas Samanta, Igor Dubenko, Abdiel Quetz, Samuel Temple, Shane Stadler, and Naushad Ali

Appl. Phys. Lett. 100, 052404 (2012); http://dx.doi.org/10.1063/1.3681798 (3 pages) | Cited 4 times

Online Publication Date: 1 February 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The thermomagnetic and magnetocaloric properties of the MnNiGe1−xAlx system have been investigated by magnetization and differential scanning calorimetry (DSC) measurements. The presence of first-order magnetostructural transitions (MSTs) from hexagonal ferromagnetic to orthorhombic antiferromagnetic phases has been detected for x = 0.085 and 0.09 at 193 K and 186 K, respectively. The values of latent heat (L = 6.6 J/g) and corresponding total entropy changes (ΔST = 35 J/kg K) have been evaluated for the MST (x = 0.09) from DSC measurements. The magnetic entropy change for x = 0.09 (ΔSM = 17.6 J/kg K for 5 T) was found to be comparable with well-known giant magnetocaloric materials, such as Gd5Si2Ge2, MnFeP0.45As0.55, and Ni50Mn37Sn13.
Show PACS
75.30.Kz Magnetic phase boundaries (including classical and quantum magnetic transitions, metamagnetism, etc.)
75.30.Sg Magnetocaloric effect, magnetic cooling
64.70.kd Metals and alloys
72.15.Jf Thermoelectric and thermomagnetic effects
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
65.40.gd Entropy

All-metallic lateral spin valves using Co2Fe(Ge0.5Ga0.5) Heusler alloy with a large spin signal

Y. K. Takahashi, S. Kasai, S. Hirayama, S. Mitani, and K. Hono

Appl. Phys. Lett. 100, 052405 (2012); http://dx.doi.org/10.1063/1.3681804 (4 pages) | Cited 4 times

Online Publication Date: 1 February 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A large spin signal (ΔRs) of 12.8 mΩ at room temperature is demonstrated in an all-metallic lateral spin valve (LSV) device comprising of ferromagnetic wire of a highly spin-polarized Co2Fe(Ge0.5Ga0.5) Heusler alloy and a Cu wire. From the results on multi-terminal LSV devices, the origin of the large ΔRs was concluded to be the high spin polarization of Co2Fe(Ge0.5Ga0.5) and the resultant small spin absorption. The all-metallic LSV device without MgO barrier has low contact resistance, which is considered to be beneficial for a high frequency ultrathin read sensor for the next generation ultrahigh density magnetic recording.
Show PACS
75.47.Np Metals and alloys
73.40.Cg Contact resistance, contact potential

Dipolar ordering of random two-dimensional spin ensemble

Andrey V. Panov

Appl. Phys. Lett. 100, 052406 (2012); http://dx.doi.org/10.1063/1.3681788 (3 pages) | Cited 1 time

Online Publication Date: 2 February 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We theoretically study the randomly positioned two-dimensional system of interacting magnetic dipoles representing the monolayer arrays of single-domain particles. It is showed the onset of the dipolar in-plane superferromagnetic ordering of Ising spins at the surface concentrations of nanoparticles above 0.24. The critical concentration of particles with random easy axis arrangement at zero temperature is 0.65. It is demonstrated that the ensemble with Ising arrangement of spins is ordered at high temperatures close to a particle Curie point.
Show PACS
75.10.Hk Classical spin models
75.50.Tt Fine-particle systems; nanocrystalline materials
75.30.Cr Saturation moments and magnetic susceptibilities
75.60.Ch Domain walls and domain structure
75.75.Fk Domain structures in nanoparticles

Anisotropy and extremely high coercivity in weak ferromagnetic LuFeO3

Wenka Zhu, Li Pi, Shun Tan, and Yuheng Zhang

Appl. Phys. Lett. 100, 052407 (2012); http://dx.doi.org/10.1063/1.3681789 (4 pages) | Cited 1 time

Online Publication Date: 2 February 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The temperature dependence of the structural anisotropy of weak ferromagnetic LuFeO3 is investigated through the XRD spectra at different temperatures. The structural anisotropy decreases with heating, which is in agreement with the magnetization-temperature measurement. The magnetic hysteresis loops reveal exceptionally high coercivity and saturation field. Its high energy of magnetocrystalline anisotropy may be responsible for the peculiar phenomenon. Thus, LuFeO3 is a super hard magnetic material. The magnetized LuFeO3 can steadily provide weak permanent magnetic field, which can be considered as a kind of useful application.
Show PACS
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.50.Dd Nonmetallic ferromagnetic materials
75.30.Gw Magnetic anisotropy
75.50.Vv High coercivity materials

Anisotropic magnetoresistance and weak spin-orbital coupling in doped ZnO thin films

Yufeng Tian, Weinan Lin, and Tom Wu

Appl. Phys. Lett. 100, 052408 (2012); http://dx.doi.org/10.1063/1.3681795 (3 pages) | Cited 5 times

Online Publication Date: 3 February 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Both out-of-plane and in-plane anisotropic magnetoresistance (AMR) of Cu-doped ZnO thin films with different crystalline orientations are studied. Comparative data of angular dependent AMR suggest that the out-of-plane AMR comes from the geometric effect, while the in-plane AMR can be attributed to the field-dependent path-length effect. Moreover, the small magnitude of AMR and the negligible magnetocrystalline anisotropy suggest that the spin-orbit coupling in Cu-doped ZnO is relatively weak.
Show PACS
75.70.Ak Magnetic properties of monolayers and thin films
75.50.Pp Magnetic semiconductors
72.20.My Galvanomagnetic and other magnetotransport effects
73.50.Jt Galvanomagnetic and other magnetotransport effects (including thermomagnetic effects)
75.30.Gw Magnetic anisotropy
68.55.J- Morphology of films

Improvement of coercivity and thermal stability of anisotropic Nd13Fe79.4B7Nb0.3Ga0.3 powders by diffusion of Pr-Cu alloys

Zhong Lin, Jingzhi Han, Meiying Xing, Shunquan Liu, Rui Wu, Changsheng Wang, Yan Zhang, Yingchang Yang, and Jinbo Yang

Appl. Phys. Lett. 100, 052409 (2012); http://dx.doi.org/10.1063/1.3681803 (4 pages) | Cited 3 times

Online Publication Date: 3 February 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Highly anisotropic Nd13Fe79.4B7Nb0.3Ga0.3 powders from a self-organized rod-like disproportionation microstructure and room temperature magnetic properties of μ0Mr = 1.4 T, iHc = 13 kOe, and (BH)max = 41 MGOe are obtained by optimizing hydrogenation disproportionation desorption recombination (HDDR) process. Diffusion of Pr68Cu32 alloy into the HDDR powders further increases the coercivity of the powders to 18 kOe. This enhancement in coercivity is mainly attributed to the modification of grain boundaries including the decrease of Fe content and the increase of boundary thickness. The modified boundaries can work as effective pinning layers for domain walls. The thermal stability of magnetic properties of HDDR powders is also improved after the diffusion treatment.
Show PACS
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.30.Gw Magnetic anisotropy
75.50.Bb Fe and its alloys
75.50.Tt Fine-particle systems; nanocrystalline materials
75.60.Ch Domain walls and domain structure
61.72.Mm Grain and twin boundaries

Multiferroic phase competitions in perovskite manganite thin films

M. H. Qin, Y. M. Tao, M. Zeng, X. S. Gao, S. J. Wu, S. Dong, and J.-M. Liu

Appl. Phys. Lett. 100, 052410 (2012); http://dx.doi.org/10.1063/1.3682079 (4 pages) | Cited 1 time

Online Publication Date: 3 February 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Based on the Mochizuki-Furukawa model, the cycloidal spin structures of orthorhombic RMnO3 manganite thin films on various magnetic substrates are simulated using Monte Carlo method. It is revealed that the long range cycloidal spin order can be modulated by the film thickness and substrate spin structure. In particular, the ferromagnetic and antiferromagnetic spin orders of the substrate in different orientations have different pinning effects on the cycloidal spin order of the thin film. The simulated results are discussed in terms of the competition between the single-ion anisotropy and spin-orbit coupling.
Show PACS
75.85.+t Magnetoelectric effects, multiferroics
75.50.Dd Nonmetallic ferromagnetic materials
75.50.Ee Antiferromagnetics
77.80.Dj Domain structure; hysteresis
77.84.Bw Elements, oxides, nitrides, borides, carbides, chalcogenides, etc.
77.55.Nv Multiferroic/magnetoelectric films

Tuning the interlayer exchange coupling between single perpendicularly magnetized CoFeB layers

R. Lavrijsen, A. Fernández-Pacheco, D. Petit, R. Mansell, J. H. Lee, and R. P. Cowburn

Appl. Phys. Lett. 100, 052411 (2012); http://dx.doi.org/10.1063/1.3682103 (5 pages) | Cited 3 times

Online Publication Date: 3 February 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We experimentally study the tunability of the Ruderman-Kittel-Kasuya-Yosida (RKKY) interlayer exchange coupling (IEC) in Pt/CoFeB/Pt/Ru/Pt/CoFeB/Pt stacks with perpendicular magnetic anisotropy (PMA). The perpendicular magnetization of a single Pt/Co60Fe20B20/Pt (at. %) shows full remanence and square hysteresis loops for a CoFeB thickness range of 0.60–1.0 nm. By inserting a Pt layer between the Ru and CoFeB, the PMA of the ultrathin CoFeB layers is stabilized and the IEC can be tuned. In particular, we show that the IEC versus Pt thickness exhibits a simple exponential decay with a decay length of 0.16 nm.
Show PACS
75.30.Et Exchange and superexchange interactions
75.30.Gw Magnetic anisotropy
75.70.Cn Magnetic properties of interfaces (multilayers, superlattices, heterostructures)
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.70.Ak Magnetic properties of monolayers and thin films
Page 2 of 5 Pages Previous Page Next Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close