Polycrystalline Bi3.15Nd0.85Ti3O12 (BNdT) thin films of a-axis preferential orientation [α(100)=62%] and high c-axis orientation [α(001)=96%] were fabricated directly on Pt∕Ti∕SiO2∕Si substrates through a sol-gel process. We observed strong dependences of ferroelectric and dielectric properties on the film orientation, with a remanent polarization 2Pr of 39μC∕cm2 and dielectric constant εr of 343 at 100 kHz in the a-axis oriented film; 2Pr of 20μC∕cm2 and εr of 331 in the film of random orientation; and 2Pr of 13μC∕cm2,εr of 218 in the highly c-axis oriented film. Furthermore, the 2Pr value of a purely a-axis-oriented BNdT film can be predicted to be ∼51μC∕cm2. The large anisotropy of 2Pr and εr values demonstrates that the polarization vector of BNdT is close to the a axis.

Articles you may be interested inStructure and electrical properties of Bi 3.15 Nd 0.85 Ti 3 O 12 nanofibers synthesized by electrospinning and sol-gel method Appl. Phys. Lett. 96, 012904 (2010); Bi 3.15 Nd 0.85 Ti 3 O 12 thin films of two different preferred orientations were sol-gel grown on Pt/ Ti/ SiO 2 / Si. Using different heating rates during crystallization, either films containing 65% columnar grains with ͑104͒ / ͑014͒ orientation or fine-grained films with a predominant c-axis orientation were obtained. Anisotropic ferroelectric and piezoelectric properties were determined, with a remanent polarization 2P r = 46.4 C/cm 2 and a piezoelectric coefficient d 33 =17 pm/V in a predominantly ͑104͒ / ͑014͒-oriented film, but only 2P r = 16.7 C/cm 2 and d 33 = 5 pm/ V in a predominantly c-axis-oriented film. These values confirm that the polarization vector of this material is close to the crystallographic a axis.

A systematic substitution of Ge, Si, C and Co for Ga in the non-stoichiometric Ni -Mn -Ga alloys was performed. The relationship between the compositions of different elements including Ni, Mn, Ga, Ge, Si, C, Co, In and martensitic transformation temperature (M s ) was studied in detail for the present alloys together with data collected from a variety of sources. It is found that M s is a sensitive parameter to the composition. The size factor and electron concentration are usually thought to be the way the composition influences M s in the Ni -Mn -Ga alloys. Here, analyzing by linear regression, the electron density maybe a most appropriate parameter to describe the way the composition influences M s when compared with size factor and electron concentration.

NiMnGaC) alloys were investigated by the measurement of resistivity. Two kinds of martensitic transformations occur in NiMnGa alloy. The first martensitic transformation is thermoelastic, which exhibits a steep increasing in resistivity. The second transformation exhibits a larger thermal hysteresis compared with the first transformation. NiMnGaC alloy only shows a single martensitic transformation and the C addition increases the first martensitic transformation temperatures. The first martensitic phase of NiMnGa alloy is of five layered structure while the martensitic phase of NiMnGaC alloy is of non-modulated structure. Combined with the observation of optical microscopy and TEM, NiMnGa alloy exhibits much wider martensite twins than NiMnGaC alloy does.

The Editors would like to inform our readers that the article "Ferroelectric anisotropy of sol -gel-derived Bi 3.15 Nd 0.85 Ti 3 O 12 thin films on SrTiO 3 single-crystal substrates" by Chen and Yang [1], published online in October 2007, has been retracted by agreement between the authors and the editors of physica status solidi. The retraction was requested by Chen due to lack of consensus among all contributors regarding publication.