Naslov
Characterization and Properties of Novel Oxygen Contained Hollandite VO1.52(OH)0.77 Nanorods Synthesized by Nonaqueous Sol-Gel Route

Autori
Djerdj, Igor ; Sheptyakov, Denis ; Gozzo, Fabia ; Arčon, Denis ; Nesper, Reinhard ; Niederberger, Markus

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Programme & abstracts of the 6th Symposium of Science and Technology of Nanomaterials in Slovenia : SLONANO 2007 / - Ljubljana : Institut Jožef Stefan, 2007

Skup
Symposium of Science and Technology of Nanomaterials in Slovenia (6 ; 2007)

Mjesto i datum
Ljubljana, Slovenija, 10.10.2007. - 12.10.2007

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
strongly correlated system; charge ordering

Sažetak
Using the nonaqueous sol-gel route based on benzyl alcohol pathway, a new compound VO1.52(OH)0.77 in the form of nanorods has been synthesized. Comprehensive structural investigations have been carried out using complementary neutron and synchrotron powder X-ray diffraction as well as different electron microscopy techniques: SEM, (HR)TEM, EDX, SAED, EELS for determination of material's morphology, crystallinity and oxidation state of vanadium. The data show that the structure can be described as hollandite-type containing only oxygen in the 2×2 channels along the c-axis, with hydrogen attached to the one octahedral-coordinating oxygen, forming thus OH− group. The nanorods are single-crystalline, up to 500 nm long and 105 nm in diameter with the growth direction along the [002] axis (Figure 1). The shape of OK edge and L3/L2 white-line ratio confirmed that the vanadium oxidation state is between 3+ and 4+ which is also deduced from the charge neutrality analysis being +3.81. Temperature dependent DC conductivity measurement evidenced Arrhenius behavior and semiconducting ground state with a band gap of 0.64 eV (cooling mode). Ab initio density-functional calculations with local spin density approximation including orbital potential (LSDA+U) predicts a direct band gap of 0.64 eV and a high degree of hybridization between O 2p and V 3d orbitals. The temperature dependence of magnetic susceptibility follows the Curie-Weiss law above 150 K. The extracted effective magnetic moment per vanadium of 1.95 B is consistent with the mixture of 3+ and 4+ oxidation states with predominant fraction of 4+.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

POVEZANOST RADA