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Transition-metal ion-doped indium oxide was potentially used in spintronic devices. In this article, 10 at.% Co- and Fe-doped indium oxide nanocrystals were, respectively, prepared by direct solvothermal method. The influences of doped ions on their morphologies and magnetic properties of indium oxide nanocrystals were investigated. It was found that the doped ions could tune the microscopic morphologies and crystalline structures of indium oxide nanoparticles. Co-doped samples were polycrystalline nanoflowers aggregated by about 5 nm nanocrystals while Fe-doped specimens were single-crystalline nanocubes with crystalline sizes of about 16 nm. Meanwhile, the magnetic transition from diamagnetism to paramagnetism was also realized by doping Co or Fe ions into the indium oxide host matrices. In addition, their magnetic properties were further demonstrated to be intrinsic and not caused by impurities. [ABSTRACT FROM AUTHOR]

Rhombohedral corundum-type metastable phase of Ni2+ doped indium oxide nanocrystals is directly synthesized via an easy LiNO3 molten salt route by dehydrated reactions of Ni2+ doped indium oxohydroxide precursors. Due to higher viscosity of molten salt solvents, their morphological transition from one-dimensional nanorods to zero-dimensional nanoparticles is realized under continuous corrosion of interfaces. Meanwhile, diluted ferromagnetism of indium oxide is also accomplished by incorporating Ni2+ ions. The mechanisms about structural evolutions and magnetic changes for Ni2+ doped indium oxide nanocrystals are discussed, too. [ABSTRACT FROM AUTHOR]

High magnetic field (HMF) treatment is an important strategy to tune the physicochemical properties of traditional materials. Here, we take nickel ion doped In 2 O 3 nanocrystals as an example and report that the magnetization behavior of diluted magnetic semiconductors can be easily tuned by HMF treatment. It is experimentally demonstrated that the room temperature ferromagnetism of lowly-doped nanocrystals can be greatly enhanced by HMF treatment while the paramagnetic properties of highly-doped samples is almost un-changed. These magnetic transition behaviors after HMF treatment are attributed to the rearrangement of magnetic ordering and the increment of grain-boundary defects. Our research not only points out an effective approach to induce the transition of spin states of diluted magnetic semiconductors but also provides a potentially efficient route to endow other traditional materials with novel physical properties. [ABSTRACT FROM AUTHOR]