153 research outputs found
Room Temperature Ferromagnetic Semiconductor Rutile Ti1-xCoxO2-\delta Epitaxial Thin Films Grown by Sputtering Method
Room temperature ferromagnetic semiconductor rutile Ti1-xCoxO2-\delta (101)
epitaxial thin films were grown on r-sapphire substrates by a dc sputtering
method. Ferromagnetic magnetization, magnetic circular dichroism, and anomalous
Hall effect were clearly observed at room temperature in sputter-grown films
for the first time. The magnetization value is nearly as large as 3\mu B/Co
that is consistent with the high spin state Co2+ in this compound recently
established by spectroscopic methods. Consequently, its originally large
magneto-optical response is further enhanced.Comment: 15 pages, 4 figure
Two distinct surface terminations of SrVO3 (001) ultrathin films as an influential factor on metallicity
Pulsed laser deposition-grown SrVO3 (001) ultrathin films on SrTiO3 (001) substrates were investigated by in situ low-temperature scanning tunneling microscopy and spectroscopy. SrVO3 (001) ultrathin films showed two distinct surface terminations. One termination was a (√2 ×√2)-R45° reconstruction as was previously observed for SrVO3 (001) thick films, while the other was a (√5 ×√5)-R26.6° reconstruction. Scanning tunneling spectroscopy revealed that the (√2 ×√2)-R45° surface shows a metallic electronic structure, whereas the (√5×√5)-R26.6° surface exhibits a significantly reduced density of states at the Fermi level. These results suggest that the surface reconstruction may be an important factor to influence metallicity in epitaxial ultrathin films of transition metal oxides
X-ray Anomalous Scattering of Diluted Magnetic Oxide Semiconductors: Possible Evidence of Lattice Deformation for High Temperature Ferromagnetism
We have examined whether the Co ions crystallographically substitute on the
Ti sites in rutile and anatase Ti_{1-x}_{x}_{2-delta}K_{1-x}_{x}_{2-delta}_2_{1-x}_{x}$O thin films and
obtained direct evidence that the Co ions are indeed substituted on the Zn
sites.Comment: 5 pages, 4 figures, accepted in PR
Width-induced metal–insulator transition in SrVO3 lateral nanowires spontaneously formed on the ultrathin film
We investigated lateral nanowires at the topmost layer of SrVO3 (001) ultrathin films using in situ low-temperature scanning tunneling microscopy and spectroscopy. The nanowires were spontaneously formed in the topmost layer of SrVO3 with a (√2 × √2)-R45° reconstruction on the terrace of a (√5 × √5)-R26.6° reconstruction. The electronic states of nanowires were significantly influenced by the nanowire width. With reducing the nanowire width from 5.5 nm to 1.7 nm, the zero-bias conductance of nanowires steeply decreased toward zero, exhibiting a metal–insulator transition possibly driven by dimensional crossover, previously observed in thickness-reduced SrVO3 ultrathin films
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