Design of compensated ferrimagnetic Heusler alloys for giant tunable exchange bias

The discovery of materials with improved functionality can be accelerated by rational material design. Heusler compounds with tunable magnetic sublattices allow to implement this concept to achieve novel magnetic properties. Here, we have designed a family of Heusler alloys with a compensated ferrimagnetic state. In the vicinity of the compensation composition in Mn-Pt-Ga, a giant exchange bias (EB) of more than 3 T and a similarly large coercivity are established. The large exchange anisotropy originates from the exchange interaction between the compensated host and ferrimagnetic clusters that arise from intrinsic anti-site disorder. We demonstrate the applicability of our design concept on a second material, Mn-Fe-Ga, with a magnetic transition above room temperature, exemplifying the universality of the concept and the feasibility of room-temperature applications. Our study points to a new direction for novel magneto-electronic devices. At the same time it suggests a new route for realizing rare-earth free exchange-biased hard magnets, where the second quadrant magnetization can be stabilized by the exchange bias.Comment: Four figure

A ‘Continuous flow’ Photochemical Water Treatment System Based on Radially Oriented ZnO Nanowires on Flexible Poly-L-Lactide Nanofibers

Several oxide ceramics, notably ZnO and TiO2 are known to catalyze decomposition of organic molecules in water under ultra-violet irradiation. Here we describe fabrication of highly flexible ZnO-based hierarchical nanostructure obtained by growing radially oriented ZnO nanowires on poly-L-lactide nanofibers. Utilizing the flexibility and high surface area of polymeric nanofibers as novel ‘substrate’ for growth of the photochemically active ZnO nanowires we show a proof-of-principle demonstration of a ‘continuous flow’ water treatment set-up. We have monitored photocatalytic decomposition of known organic pollutants, such as methylene blue, monocrotophos and diphenylamine under illumination with ultraviolet light using this highly flexible hierarchical nanostructure.QC2010061

Room temperature ferromagnetism in Ce 1-xFe xO 2-δ(x = 0.0, 0.05, 0.10, 0.15 and 0.20) nanoparticles synthesised by combustion method

Nanocrystalline Ce1−xFexO2− particles with different Fe concentrations (x = 0.0, 0.05, 0.10, 0.15, and 0.20) have been prepared by a gel-combustion method. X-ray diffraction data revealed the formation of an impurity free Ce1−xFexO2− products up to x = 0.15. This observation is further confirmed from the detailed studies conducted on 10 at.% Fe doped CeO2 using High-Resolution Transmission Electron Microscopy (HRTEM) imaging, Selected-Area Electron Diffraction (SAED) and Raman spectroscopy. DC magnetization studies as a function of field and temperature indicate that they are ferromagnetic with Curie temperature (Tc) well above room temperature

A ‘Continuous flow’ Photochemical Water Treatment System Based on Radially Oriented ZnO Nanowires on Flexible Poly-L-Lactide Nanofibers

Several oxide ceramics, notably ZnO and TiO2 are known to catalyze decomposition of organic molecules in water under ultra-violet irradiation. Here we describe fabrication of highly flexible ZnO-based hierarchical nanostructure obtained by growing radially oriented ZnO nanowires on poly-L-lactide nanofibers. Utilizing the flexibility and high surface area of polymeric nanofibers as novel ‘substrate’ for growth of the photochemically active ZnO nanowires we show a proof-of-principle demonstration of a ‘continuous flow’ water treatment set-up. We have monitored photocatalytic decomposition of known organic pollutants, such as methylene blue, monocrotophos and diphenylamine under illumination with ultraviolet light using this highly flexible hierarchical nanostructure.QC2010061

Multi-band conduction behaviour at the interface of LaAlO3/SrTiO3 heterostructures

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