ROOM-TEMPERATURE FERROMAGNETISM IN 2 NANOFIBERS AND NANOTUBES PREPARED BY ELECTROSPINNING.

2 nanofibers and nanotubes were synthesized by electrospinning method. Magnetization measurement indicates that the 2 nanofibers and nanotubes annealed in air at 500°C exhibit the room-temperature ferromagnetism and the ferromagnetism of nanotubes is stronger than the nanofibers. Selected area electron diffraction, X-ray diffraction and Raman measurements show that all the samples possess a typical rutile structure and no other impurity phases are observed. The results of the Raman spectra also indicate that there are lots of defects existing in the fabricated samples. The observed room-temperature ferromagnetism in 2 nanofibers and nanotubes possibly originates from oxygen vacancies. The field cooled (FC) and zero-field-cooled (ZFC) magnetization curves indicate that the Curie temperature TC is above 300 K. SnO2 nanofibers and nanotubes were synthesized the electrospinning method. The observed room-temperature ferromagnetism originates from surface defects. [ABSTRACT FROM AUTHOR]