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The anisotropy field of FePt L1 0 nanoparticles controlled by very thin Pt layer

2004; IOP Publishing; Volume: 16; Issue: 12 Linguagem: Inglês

10.1088/0953-8984/16/12/020

1361-648X

Satoshi Okamoto, O. Kitakami, Nobuaki Kikuchi, Takamichi Miyazaki, Yutaka Shimada, Te-Hsuan Chiang,

Semiconductor materials and interfaces

We have prepared epitaxial FePt L10 (001) nanoparticles covered with Pt [dPt nm]/Ag[(4−dPt) nm] overlayers. The particles are oblate spheroids approximately 10 nm in diameter and 2 nm in height. The anisotropy field Hk at 0 K, which is evaluated from the temperature dependences of coercivity Hc, decreases from 90 to 60 kOe on increasing the Pt thickness from dPt = 0 to 1.5 nm, while the energy barrier at zero field remains unchanged. The significant reduction of Hk due to the presence of the adjacent Pt layer can be attributed to an enhanced magnetic moment caused by the ferromagnetic polarization of Pt atoms at the interface. This finding suggests an effective method of controlling the switching field of FePt L10 nanoparticles.