Atomistic modeling of magnetization reversal modes in L1(0) FePt nanodots with magnetically soft edges

作者：Liao Jung Wei^*; Atxitia Unai; Evans Richard F L; Chantrell Roy W; Lai Chih Huang

来源：Physical Review B, 2014, 90(17): 174415.

DOI：10.1103/PhysRevB.90.174415

Nanopatterned FePt nanodots often exhibit low coercivity and a broad switching field distribution, which could arise due to edge damage during the patterning process causing a reduction in the L1(0) ordering required for a high magnetocrystalline anisotropy. Using an atomistic spin model, we study the magnetization reversal behavior of L1(0) FePt nanodots with soft magnetic edges. We show that reversal is initiated by nucleation for the whole range of edge widths studied. For narrow soft edges the individual nucleation events dominate reversal; for wider edges, multiple nucleation at the edge creates a circular domain wall at the interface which precedes complete reversal. Our simulations compare well with available analytical theories. The increased edge width further reduces and saturates the required nucleation field. The nucleation field and the activation volume manipulate the thermally induced switching field distribution. By control of the properties of dot edges using proper patterning methods, it should be possible to realize exchange spring bit-patterned media without additional soft layers.

• 出版日期2014-11-13
• 单位清华大学