Research on magnetism in reduced dimensionality is both important for basic science study of low-dimensional physics and for magnetic data storage as well as other spintronic applications. The experimental studies of two-dimensional magnetism started in 1970s and the continuous effort of researchers has finally resulted in the milestone discovery of giant magnetoresistance (GMR) in 1988. In 1990s, researchers started to put attention on magnetic materials in one- (1D) and zero-dimensions (0D). Jian Shen has led the pioneer effort to clarify the superparamagnetic nature of 1D stripe, and successfully overcome the superparamagnetic limit of 0D quantum dots by introducing the surface states mediated electronic interactions. The study of 0D magnetic quantum dots are not only important for high-density data storage, but also valuable for organic spintronic devices.
References:
1. Giant Magnetoresistance in Organic Spin Valves, Dali Sun, Lifeng Yin, Chengjun Sun, Hangwen Guo, Zheng Gai, X.-G. Zhang, T. Z. Ward, Zhaohua Cheng, and Jian Shen*, Phys. Rev. Lett. 104, 236602 (2010)
2. Tuning the Ferromagnetic Coupling of Fe Nanodots on Cu(111) via Dimensionality Variation of the Mediating Electrons, Lifeng Yin, Di Xiao, Zheng Gai, Thomas Z. Ward, Noppi Widjaja, G. Malcolm Stocks, Zhao-hua Cheng, E. Ward Plummer, Zhenyu Zhang, and Jian Shen*, Phys. Rev. Lett. 104, 167202 (2010).
3. “Live” Surface Ferromagnetism and Ferromagnetic to Spin-glass Phase Transition in Fe Nanodots/Cu Multilayers on Cu(111), M.A. Torija, A.P. Li, X. C. Guan, E.W. Plummer, and J. Shen*, Phys. Rev. Lett. 95, 257203 (2005).
4. Frozen Low Spin Interface in Ultrathin Films of Fe on Cu(111), M.A. Torija, Z. Gai, N. Myoung, E.W. Plummer, and J. Shen*, Phys. Rev. Lett. 95, 27201 (2005).
5. Ferromagnetic Stability in Fe Nanodot Assemblies on Cu(111) Induced by Indirect Coupling through the Substrate, J. P. Pierce, M.A. Torija, Z. Gai, Junren Shi, T.C. Schulthess, G.A. Farnan, J. F. Wendelken, E.W. Plummer, and J. Shen*, Phys. Rev. Lett. 92, 237201 (2004).
6. Magnetic moment of fcc Fe(111) ultrathin films by ultra-fast deposition on Cu(111), J. Shen, P. Ohresser, Ch.V. Mohan, M. Klaua, J. Barthel, and J. Kirschner, Phys. Rev. Lett. 80, 1980 (1998)
7. Magnetism in one dimension: Fe on Cu(111), J.Shen, R.Skomski, M.Klaua, H.Jenniches, S.S.Manoharan, and J.Kirschner, Phys. Rev. B 56, 2340 (1997).
8. Structural and magnetic phase transitions of Fe on stepped Cu(111), J. Shen, M. Klaua, P. Ohresser, H. Jenniches, J. Barthel, Ch.V. Mohan, and J. Kirschner, Phys. Rev. B 56, 11134 (1997)
