Atomic scale one-dimensional magnet


Atomic scale one-dimensional magnet

-Ferromagnetic dislocations embedded in antiferromagnetic crystal-


A group led by Professor Yuichi Ikuhara of the University of Tokyo, who is also PI of AIMR, with cooperation from Assistant Professor Zhongchang Wang of AIMR have found that the dislocations introduced into antiferrromagnetic nickel oxide show ferromagnetic property with extremely high magnetic coercivity and they revealed that the ferromagnetic behavior of the dislocations is according to the Ni vacancies introduced along the dislocations.

Dislocations ―“tunnels” like one-dimensional lattice defects in crystals with locally distinct atomic-scale structures were thought to be harmful for electric or magnetic materials and devices, however, Prof. Ikuhara’s group is focusing on unique property of one-by-one dislocations because they can be applied for various nano-devices. In this study, dislocations introduced into non-magnetic nickel oxide were revealed to show ferromagnetic property. The ferromagnetic dislocations introduced into nickel oxide are extremely hard to switch polarity. The ferromagnetic property was revealed to be because of nickel atomic vacancies introduced along the dislocations by combining atomic-resolution scanning transmission electron microscopy observations, electron energy loss spectroscopy analysis and theoretical calculations by super computer.

These hard nano-magnet can be applied for pinned layer in magnetic memories and the memories can be miniaturized into 1/10,000 size using the results of this study.


Issei Sugiyama, Naoya Shibata, Zhongchang Wang, Shunsuke Kobayashi, Takahisa Yamamoto, Yuichi Ikuhara, "Ferromagnetic dislocations in antiferromagnetic NiO" Nature Nanotechnology 8, 266–270 (2013) (Abstract) (will open in a new tab)