Strong Pinned-Spin-Mediated Memory Effect in NiO Nanoparticles.
After a decade of effort, a large number of magnetic memory nanoparticles with different sizes and core/shell compositions have been developed. While the field-cooling memory effect is often attributed to particle size and distribution effects, other magnetic coupling parameters such as inter- and intra-coupling strength, exchange bias, interfacial pinned spins, and the crystallinity of the nanoparticles also have a significant influence on magnetization properties and mechanisms. In this study, we used the analysis of static- and dynamic-magnetization measurements to investigate NiO nanoparticles with different sizes and discussed how these field-cooling strengths affect their memory properties. We conclude that the observed field-cooling memory effect from bare, small size NiO nanoparticles arises because of the unidirectional anisotropy which is mediated by the interfacial strongly pinned spins.
Department of Physics, National Dong Hwa University, Hualien, 97401, Taiwan.|Center for Condensed Matter Sciences, National Taiwan University, Taipei, Taiwan.
Ashish Chhaganlal
AC
Gandhi
National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan.
Ting Shan
TS
Chan
Department of Physics, Abasaheb Garware College, Savitribai Phule Pune University, Pune, India.
Jayashree
J
Pant
Department of Physics, National Dong Hwa University, Hualien, 97401, Taiwan. sywu@mail.ndhu.edu.tw.
Sheng Yun
SY
Wu
Interfacial pinned spins; Memory effect; NiO nanoparticles