Narrow Results

Anomalous strong linear anisotropy of resonant Raman scattering in open ZnCdSe/ZnSe nanowires has been found. The anisotropy value is more than twice as that due to the anisotropy of exciton–photon interaction which is the characteristic for open nanowires. It is suggested that the anomalous anisotropy is connected with different probability of Frohlich exciton–LO phonon interaction at scattering via transverse and longitudinal exciton states.

The formation of β- and γ-cyclodextrin (CD) nanotubes induced by the molecule 4,4′-bis(2-benzoxazolyl) stilbene (BOS) was investigated by fluorescence anisotropy. Using the Perrin–Webber formula, the average number of cyclodextrin (n_CD) in each nanotube was estimated and the results suggested that the n_CD value in the γ-CD system is larger than that in the β-CD system. Hydrogen-bonding between the hydroxyl groups of neighboring CDs was found to be an important contribution to the formation of cyclodextrin nanotube on the basis of the pH effect study. The temperature effect study showed that this nanotube was thermostable at T ≤ 303 K, while it was gradually collapsed at higher temperature.

The aim of this report is to prove that polarimetric surface plasmon resonance imaging (P-SPRI) is able to characterize dynamically the anisotropy of micro and nanoobjects. Micro and nanoparticles were assembled into filaments at a specific location on a support, using a combination of magnetic field, amine based chemistry and orthogonal surface chemistry. After immobilization of the filaments onto gold pads, they were actuated by a magnetic field and validated the P-SPRI system.

Nanocrystalline cobalt–ferrite particles of size 20–30 nm have been prepared by a reverse coprecipitation technique under the assistance of ultrasonic irradiation and heat-treatment at different temperatures (from 473 K to 1073 K). Both X-ray diffraction and transmission electron microscope analysis confirms the reduction of strain present in the material with annealing temperature. Enhancement of coercivity and magnetization value has been observed without increase in the particle size for whole range of annealing temperature. Temperature dependent magnetization loop shows considerable magnetic hardening at low temperature. The observed enhancement of the coercivity value has been attributed to the increase in magneto-crystalline anisotropy, surface effects and exchange anisotropy. The mechanical properties of the pure cobalt–ferrite samples and cobalt–ferrite reinforced alumina samples were also examined. The Vickers microhardness and the compressive properties obtained from the stress–strain relation showed higher value with annealing temperatures and higher nanoparticle content.

Bismuth ferrite (BiFeO${}_3)$ nanorods have been prepared from 2-methoyethanol (2-MOE)-assisted sol–gel technique. Structure, dielectric, and magnetic properties of BiFeO₃ nanorods are briefly discussed in this paper. Fourier-transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) results suggest that the BiFeO₃ peaks calcined at 500^∘C exhibit a distorted rhombohedral perovskite structure with the absence of other secondary phases like Bi₂Fe₄O₉. Meanwhile, the BiFeO₃ showed excellent photoluminescence (PL) behavior due to the transmission of electrons from conduction band to the valence band. Ferroelectric hysteresis loop of BiFeO₃ shows an increase of coercivity from 5.5–6$\mu$C/cm² in a frequency range of 6–12kHz. The magnetization measurement resulted in a well-saturated ferromagnetic behavior, and in addition, the temperature-dependent magnetization was discussed for BiFeO₃ nanorod using superconducting quantum interference device (SQUID) method. The zero-field-cooled (ZFC) and field-cooled (FC) curves reveal spin-glass effect owing to size effects, spin exchange, and anisotropy of material assembly.