Dresden 2017 – scientific programme

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MA: Fachverband Magnetismus

MA 15: Magnetic Heuslers, Half-metals and Oxides (jointly with TT)

MA 15.10: Talk

Monday, March 20, 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 Chu^2,3, 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.