| Budget Amount *help |
¥47,710,000 (Direct Cost: ¥36,700,000、Indirect Cost: ¥11,010,000)
Fiscal Year 2011: ¥6,240,000 (Direct Cost: ¥4,800,000、Indirect Cost: ¥1,440,000)
Fiscal Year 2010: ¥6,760,000 (Direct Cost: ¥5,200,000、Indirect Cost: ¥1,560,000)
Fiscal Year 2009: ¥34,710,000 (Direct Cost: ¥26,700,000、Indirect Cost: ¥8,010,000)
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| Research Abstract |
In order to develop a memory cell material which is applicable to high density magnetic random access memory (MRAM), the composition dependence on saturation magnetization Ms, perpendicular magnetic anisotropy constant Ku and Gilbert damping constant . have been investigated in epitaxial Mn_xGa_<1-x> (0. 5≦x≦0. 75)alloy films. The M_s values decrease linearly from approximately 600 to 200 emu/cc with increasing x, where as the K_u values decrease slightly from 15 to 10 Merg/cc with increasing x. The damping constant . is 0. 08 (0. 015)for Mn_<1. 54> Ga (Mn_<2. 12> Ga)film. These magnetic properties satisfy the requirement for memory cell.
Furthermore, by using Mn-Ga alloy films as the electrode of tunnel junction, we investigated the magnetoresistance ratio at 10 K and 300 K. With an insertion of Fe (Co)between Mn-Ga electrode and tunnel barrier the maximum TMR value up to 60 (40)%is obtained at room temperature. An increase of TMR value is necessary for MRAM memory cell.
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