Surface-Spin Driven Room Temperature Magnetic Memory Effect in Fe-substituted NiO Nanoparticles

Ashish Gandhi^1*, Hsin-Hao Chiu¹, Kuan-Ting Wu¹, Chia-Liang Cheng¹, Sheng Yun Wu¹

¹Department of Physics, National Dong Hwa University, Hualien, Taiwan

* Presenter:Ashish Gandhi, email:acg.gandhi@gmail.com

We report a possible route to achieve room temperature (RT) magnetic memory effect (MME) simply by thermal treatment from barely 1 % Fe-substituted NiO nanoparticles. The post-annealing of Ni_0.99Fe_0.01O nanoparticles leads to the formation of a Fe-rich NiO surface, resulting in an enhanced collective spin behavior because of the increase in interparticle interaction. This surface-spin-driven collective spin behavior provided additional anisotropic energy leading to the occurrence of RT MME. This study demonstrates an approach to tune the magnitude of MME simply by controlling the post-annealing temperature for 1 % Fe-dopant concentration. The proposed method opens a route for implementing RT spintronic devices and a deeper understanding of their fundamental physics.

Keywords: Fe-substituted NiO, magnetic memory effect., surface state, nanoparticles, exchange bias