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

11 Oct 2010

Volume 97, Issue 15, Articles (15xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 97, 154101 (2010); http://dx.doi.org/10.1063/1.3479052 (3 pages)

Younggeun Park, Yeonho Choi, Debkishore Mitra, Taewook Kang, and Luke P. Lee
Enlarge Image | Read More
Return to All Sections
back to top
RSS Feeds

Strain-driven phase transitions and associated dielectric/piezoelectric anomalies in BiFeO3 thin films

C. W. Huang, Y. H. Chu, Z. H. Chen, Junling Wang, T. Sritharan, Q. He, R. Ramesh, and Lang Chen

Appl. Phys. Lett. 97, 152901 (2010); http://dx.doi.org/10.1063/1.3499658 (3 pages) | Cited 6 times

Online Publication Date: 11 October 2010

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Strain-driven phase transitions and related intrinsic polarization, dielectric, and piezoelectric properties for single-domain films were studied for BiFeO3 using phenomenological Landau–Devonshire theory. A stable and mixed structure between tetragonal and rhombohedral-like (monoclinic) phases is predicted at a compressive misfit strain of um = −0.0382 without an energy barrier. For a tensile misfit strain of um = 0.0272, another phase transition between the monoclinic and orthorhombic phases was predicted with sharply high dielectric and piezoelectric responses.
Show PACS
77.84.Bw Elements, oxides, nitrides, borides, carbides, chalcogenides, etc.
77.55.hn Other piezoelectric or electrostrictive films
77.65.Ly Strain-induced piezoelectric fields
77.80.bn Strain and interface effects
77.80.Dj Domain structure; hysteresis
77.22.Ej Polarization and depolarization

Phase coexistence near a morphotropic phase boundary in Sm-doped BiFeO3 films

S. B. Emery, C.-J. Cheng, D. Kan, F. J. Rueckert, S. P. Alpay, V. Nagarajan, I. Takeuchi, and B. O. Wells

Appl. Phys. Lett. 97, 152902 (2010); http://dx.doi.org/10.1063/1.3481065 (3 pages) | Cited 11 times

Online Publication Date: 12 October 2010

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have investigated heteroepitaxial films of Sm-doped BiFeO3 with a Sm-concentration near a morphotropic phase boundary. Our high-resolution synchrotron x-ray diffraction, carried out in a temperature range of 25 to 700 °C, reveals substantial phase coexistence as one changes temperature to crossover from a low-temperature PbZrO3-like phase to a high-temperature orthorhombic phase. We also examine changes due to strain for films exhibiting anisotropic misfit between film and substrate. Additionally, thicker films exhibit a substantial volume collapse associated with the structural transition that is suppressed in thinner films.
Show PACS
68.55.A- Nucleation and growth
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy
81.30.Hd Constant-composition solid-solid phase transformations: polymorphic, massive, and order-disorder

Sign reversal in the dielectric anisotropy as functions of temperature and frequency in the nematic phase of a bent-core mesogen

Yun Jang, Vitaly P. Panov, C. Keith, C. Tschierske, and J. K. Vij

Appl. Phys. Lett. 97, 152903 (2010); http://dx.doi.org/10.1063/1.3498674 (3 pages) | Cited 2 times

Online Publication Date: 12 October 2010

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The sign reversal in the dielectric anisotropy (ϵ∥′−ϵ⊥′) from positive to negative is observed for 4-cyanoresorcinol bisbenzoate system with temperature and frequency in the nematic phase of a bent-core system as the temperature is reduced. This cross-over in dielectric anisotropy is such that at temperatures much below the cross-over temperature, the negative anisotropy is found to be independent of frequency. The experimental observation is supported by results from optical transmittance spectroscopy. This observation is suggested to arise from the following two sources: the presence of cybotactic clusters found by x-ray scattering in the same compound in its nematic phase and conformers that may change the bent core angle at a certain temperature as observed by nuclear magnetic resonance in a similar compound.
Show PACS
77.84.Nh Liquids, emulsions, and suspensions; liquid crystals
61.30.Gd Orientational order of liquid crystals; electric and magnetic field effects on order
64.70.mj Experimental studies of liquid crystal transitions
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
77.22.Ch Permittivity (dielectric function)
71.45.Gm Exchange, correlation, dielectric and magnetic response functions, plasmons

Pt-assisted oxidation of (100)-Ge/high-k interfaces and improvement of their electrical quality

Christoph Henkel, Ole Bethge, Stephan Abermann, Stefan Puchner, Herbert Hutter, and Emmerich Bertagnolli

Appl. Phys. Lett. 97, 152904 (2010); http://dx.doi.org/10.1063/1.3500822 (3 pages) | Cited 5 times

Online Publication Date: 12 October 2010

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report on the improvement of electrical quality of (100)-Ge/high-k-dielectric interfaces by introducing thin Pt top layers on the dielectric and subsequent oxidative treatments or using a Pt-deposition process with inherent oxidative components. Here, deposition of thin physical vapor deposition-Pt layers, combined with subsequent oxygen treatments, or oxygen assisted atomic layer deposition of Pt on these dielectrics, is applied. Strong reduction of interface trap densities down to mid-1011 eV−1 cm−2 is achieved. The approach is shown for Pt/ZrO2/La2O3/Ge, Pt/ZrO2/GeO2/Ge, and Pt/ZrO2/Ge gate stacks. By x-ray photoelectron spectroscopy evidence is given for oxygen enrichment at Ge/high-k-dielectric interfaces, to be responsible for the improved electrical properties.
Show PACS
81.65.Mq Oxidation
73.61.Cw Elemental semiconductors
79.60.Bm Clean metal, semiconductor, and insulator surfaces
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close