Magnetic properties in α-MnO2 doped with alkaline elements

• Published in: Scientific reports Vol. 5; no. 1; p. 9094
• Main Authors: Tseng, Li-Ting, Lu, Yunhao, Fan, Hai Ming, Wang, Yiren, Luo, Xi, Liu, Tao, Munroe, Paul, Li, Sean, Yi, Jiabao
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 13.03.2015; Nature Publishing Group
• Subjects: 119/118; 140/146; 639/301/119/2793; 639/301/357/997; Humanities and Social Sciences; multidisciplinary; Science
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep09094

α-MnO 2 nanotubes were fabricated using a hydrothermal technique. Li, Na and K ions were introduced into MnO 2 nanotubes to tailor their magnetic properties. It was found that with a doping concentration lower than 12 at%, the nanotubes showed ferromagnetic-like ordering at low temperature (<50 K), while antiferromagnetic coupling dominated their physical behavior with doping concentrations beyond 12 at%. Such experimental phenomenon was in very good agreement with associated first principle calculations. The ferromagnetic-like ordering originates from the breaking of equivalence between two different Mn-O octahedrals in α-MnO 2 due to the filling of alkaline ions in the tunnels. Both small charge transfer and lattice distortion play important roles in the ferromagnetic ordering.