Modulation of magnetism through interface properties and reversible hydrogenation
Wen-Chin Lin1*
1Department of Physics, National Taiwan Normal University, Taipei, Taiwan
* presenting author:林(Lin)文欽(Wen-Chin),
In low dimensional magnetic materials, the symmetry breaking and high ratio of surface atoms to volume atoms open a window for the manipulation of magnetic anisotropy energy by modifying the surface or interface properties. Therefore in our recent studies, we demonstrated the modulation of magnetism in ultrathin films and magnetic structures through the reversible hydrogenation, interface oxidation, and bias voltage.
Nano-structured Fe coverage was deposited on Pd/W{112} faceting surface for the investigation of magnetic properties. Hydrogen adsorption significantly enhanced the perpendicular coercivity by 6-7 times, and shifted the switching critical thickness to 2.8 PML.[1] Annealed Pd/Co/Pd trilayers grown on Al2O3(0001) revealed perpendicular magnetization due to the Co-Pd alloy formation at interface. Hydrogen-absorption can induce significant effects on the magnetic anisotropy. Reversible modification of 20% magnetic coercivity was observed. The response time is within 50 sec and the reversibility is also demonstrated.[2] The magnetic coercivity (Hc) of Fe/ZnO heterostructure was significantly enhanced by 2–3 times after applying a suitable current. This Hc enhancement originates from the Fe-oxidation at the Fe/ZnO interface induced by direct current heating.[3] Our study also demonstrated the reversible voltage-control of magnetism in Fe/ZnO heterostruture, proposing ZnO as an efficient material to provide electromechanical coupling to a magnetic overlayer.[4]

< Reference >
[1] C.C. Chiu, W.C. Lin*, Y.C. Yeh, and K.J. Song*, Appl. Phys. Lett. 102, 242403 (2013).
[2] W.C. Lin*, C.J. Tsai, C.H. Kao, B.Y. Wang, W.F. Pong, Appl. Phys. Lett. 102, 252404 (2013).
[3] W.C. Lin*, P.C. Chang, C.J.Tsai, T.C. Hsieh, and F.Y. Lo*, Appl. Phys. Lett. 103, 212405 (2013).
[4] W.C. Lin*, P.C. Chang, C.J.Tsai, T.C. Hsieh, and F.Y. Lo*, Appl. Phys. Lett. 104, 062411 (2014).

Keywords: Hydrogenation, Magnetic thin film