Dresden 2017 – wissenschaftliches Programm
MA 15.10: Vortrag
Montag, 20. März 2017, 17:30–17:45, HSZ 403
Colossal increase in the magnetic moment of NiCo2O4 films via He-ion irradiation — •Parul Pandey1, Yugandhar Bitla2, Matthias Zschornak1, Mao Wang1, Chi Xu1, Joerg Grenzer1, Sibylle Gemming1, Manfred Helm1, Ying-Hao Chu2,3, and Shengqiang Zhou1 — 1Helmholtz-Zentrum-Dresden -Rossendorf, Dresden, Germany — 2National Chiao Tung University, Hsinchu, Taiwan — 3Institute of Physics, Academia Sinica, Taipei, Taiwan
The spinel NiCo2O4 exhibits the unique combination of electrical conductivity, infrared transparency, electro catalytic activity, and ferrimagnetic order, which makes it an attractive material for spintronic applications. The NiCo2O4 thin-films electrical and magnetic properties can be manipulated from high temperature ferrimagnetic and metallic to low temperature ferromagnetic and insulating by changing the growth temperature. The high-quality epitaxial NiCo2O4 films were grown on MgAl2O4 (100) substrate at ~ 400°C exhibits metallic behavior accompanied by ferrimagnetic order with moment ~ 2 μB/fu. Here, we report the impact of He-ion irradiation with fluence ranging from 5*1015/cm2 - 3*1016/cm2 on these metallic NiCo2O4 films. The use of He-ion irradiation results in the coherent control of out-of-plane lattice parameter of these films without changing its in-plane lattice parameter. The comprehensive study of magnetization data reveals the magnetic moment in the irradiated films increases drastically to ~ 4 μB/fu. The X-ray absorption spectroscopic study also suggests the possible charge redistribution within the octahedral sites of the NiCo2O4 films which corroborate well with the increase in the magnetic moment.