Regensburg 2013 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
DF: Fachverband Dielektrische Festkörper
DF 12: Poster 1
DF 12.71: Poster
Dienstag, 12. März 2013, 10:30–13:30, Poster D
Pressure induced Ferromagnetism in undoped ZnO pellets — •Chen Yu-Chun1, Eberhard Goering1, Zumin Wang1, Lars Jeurgens2, Thomas Tietze1, and Gisela Schütz1 — 1Max Planck Institute for Intelligent System, Stuttgart, Germany — 2Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, Switzerland
Room-temperature ferromagnetism (RTFM) has been found in undoped ZnO thin film1-2 and nanostructures3-4 even though bulk samples exhibit no ferromagnetic ordering. This unexpected phenomenon is still controversial; however, numerous reports have reconfirmed the presence of RTFM in ZnO and excluded unintended contribution from impurities. The origin of RTFM in d0 oxides is not yet fully understood. It is assumed that this amazing property could be ascribed to surface oxygen vacancies2,4. In our study we present that RTFM can be induced in bulk ZnO by pressing pure non-ferromagnetic ZnO nanoparticles into pellets. The possible mechanism behind this finding is short-range interaction between isolated spin moments is achieved after mechanical compression. The RTFM behavior can be further enhanced in post-annealed pellets. XPS analysis suggests that more oxygen-related vacancies created after thermal treatment play a crucial rule in this ferromagnetic behavior. It is also found that a carbon-free surface can facilitate the interaction between isolated spin moments. References 1. N. H. Hong, et al., J. Phys: Condens. Matter. 19, 036219 , 2007 2. P. Zhan, et al., J. Appl. Phys. 111, 033501, 2012 3. S. Banerjee, et al., 182501, 2007 4. J. I. Hong, et al., Nano Lett. 12, 576, 2012