http://files.janapv.webnode.cz/200000097-8a03f8afdf/ex_bias_nano.pdf

Exchange bias in nanostructures

Nanocomposites, a high performance material exhibit unusual property combinations and unique design possibilities. With an estimated annual growth rate of about 25% and fastest demand to be in engineering plastics and elastomers, their potential is so striking that they are useful in several areas ranging from packaging to biomedical applications. In this unified overview the three types of matrix nanocomposites are presented underlining the need for these materials, their processing methods and some recent results on structure, properties and potential applications, perspectives including need for such materials in future space mission and other interesting applications together with market and safety aspects. Possible uses of natural materials such as clay based minerals, chrysotile and lignocellulosic fibers are highlighted. Being environmentally friendly, applications of nanocomposites offer new technology and business opportunities for several sectors of the aerospace, automotive, electronics and biotechnology industries.

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Nanocomposites: synthesis, structure, properties and new application opportunities

CuO nanostructures: Synthesis, characterization, growth mechanisms, fundamental properties, and applications

Synthesis and magnetic properties of cobalt ferrite (CoFe2O4) nanoparticles prepared by wet chemical route

Strategies of making TiO2 and ZnO visible light active.

Synthesis and magnetic characterization of nickel ferrite nanoparticles prepared by co-precipitation route

Magnetization of sol–gel prepared zinc ferrite nanoparticles: Effects of inversion and particle size

We report the crystal structure and magnetic properties of Zn1−xCoxO (0≤x≤010) nanoparticles synthesized by heating metal acetates in organic solvent The nanoparticles were crystallized in the wurtzite ZnO structure after annealing in air and in a forming gas (Ar95% + H5%) The x-ray diffraction and x-ray photoemission spectroscopy (XPS) data for different Co content show clear evidence for the Co2+ ions in tetrahedral symmetry, indicating the substitution of Co2+ in the ZnO lattice However, samples with x = 008 and higher cobalt content also indicate the presence of Co metal clusters Only those samples annealed in the reducing atmosphere of the forming gas, that showed the presence of oxygen vacancies, exhibited ferromagnetism at room temperature The air annealed samples remained non-magnetic down to 77 K The essential ingredient in achieving room temperature ferromagnetism in these Zn1−xCoxO nanoparticles was found to be the presence of additional carriers generated by the presence of the oxygen vacancies

http://www.physics.udel.edu/~ismat/paper1/20061.pdf

Effect of reducing atmosphere on the magnetism of Zn1?xCoxO (0?x?0.10) nanoparticles

Optical and magnetic studies on CuO nanoparticles prepared by a chemical route are reported and the effect of size variation on these properties is discussed. SEM images show that the nanoparticles are interlinked into microspheres with the cages containing visible nanoscale holes. Diffuse reflectance spectroscopy indicates a consistent red shift in the fundamental band gap (indirect band gap) from 1.23 to 1 eV as the size decreases from 29 to 11 nm. This observed red shift is attributed to the presence of defect states within the band gap. A clear blue shift is observed in the direct band gap of these nanoparticles presumably due to the quantum confinement effects. Air-annealed samples show a paramagnetic response whereas particles annealed in a reducing atmosphere show additionally a weak ferromagnetic component at room temperature. For both types of particles, the paramagnetic and ferromagnetic moments, respectively, increase with decreasing size. The role of oxygen vacancies is understood to relate to the generation of free carriers mediating ferromagnetism between Cu spins. AC susceptibility measurements show both the antiferromagnetic transitions of CuO including the one at 231 K which is associated with the onset of the spiral antiferromagnetic phase transition.

S. K. Hasanain

Papers

Synthesis and magnetic properties of cobalt ferrite (CoFe2O4) nanoparticles prepared by wet chemical route

Synthesis and magnetic characterization of nickel ferrite nanoparticles prepared by co-precipitation route

Magnetization of sol–gel prepared zinc ferrite nanoparticles: Effects of inversion and particle size

Effect of reducing atmosphere on the magnetism of Zn1?xCoxO (0?x?0.10) nanoparticles

Size effects on the magnetic and optical properties of CuO nanoparticles