Domain Shape of CGC-like Films with Under Layer of Periodic Isolated FePt Particles(MORIS 2007 Workshop on Thermal & Optical Magneitc Materials and Devices)

概要

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We reported simulated results of coupled granular and continuous (CGC)-like film, consisting of FePt granular under layer that act as a domain pinning of TbFeCo layer. For further increasing the recording density, grain diameter and period of each grain p have to be decreased until comparable scale with the domain wall width W_d and it causes difficulty to predict the domain structure. Simulated result shows it could be formed on p ≅ W_d (domain diameter D_d = 25 nm), which domain size is suitable to 1 Tbit/inch^2. Moreover, we clarified that D_d = 22 nm (it is suitable at 1.33 Tbit/inch^2) at the TbFeCo surface and domain shape could be formed even under the condition of p < W_d. And we estimated the effective wall coercivity H_w, from the simulation varying the applied magnetic field until domain is shrank and disappear. Suitable value of H_w (>10kOe) was observed. Furthermore, to elucidate the details of this contribution by interfacial exchange coupling we carried out simulations while varying the values of interfacial exchange constant A_<int> over wide range. The observed pinning effect can be attributed to interfacial exchange coupling even much smaller value of A_<int> (< 0.047×10-6 erg/cm) comparing with A of TbFeCo (0.2×10-6 erg/cm) and FePt (1.13×10-6 erg/cm).
2008-03-01