[10p-W323-1~16] 6.4 Thin films and New materials

▲ [10p-W323-16] Buffer layers dependence of magnetic properties for C38-type MnGaGe films

〇(DC)Mingling Sun^1,2, Takahide Kubota^2,3, Yoshiaki Kawato⁴, Shigeki Takahashi⁴, Yoshiaki Sonobe⁴, Koki Takanashi^2,3 (1.Grad. Sch. of Eng, Tohoku Univ., 2.IMR, Tohoku Univ., 3.CSRN, Tohoku Univ., 4.Samsung R&D Institute Japan)

Keywords:uniaxial magnetic anisotropy

We are focusing on C38-type MnGaGe ordered alloy films. In our previous work, epitaxially grown Mn₃₃Ga₃₆Ge₃₁ films which are close to the stoichiometry were deposited on MgO (100) substrates directly. The maximum value of K_u was ~ 8 × 10⁶ erg/cm³ in the sample with a 100-nm-thick Mn₃₃Ga₃₆Ge₃₁ layer annealed at 500 ºC [2]. In addition, perpendicular magnetization was achieved for the thickness of Mn₃₃Ga₃₆Ge₃₁ layer down to 10 nm. However, the squareness of the magnetization curves was poor, which was probably because of relatively large orientation dispersion. In this presentation, we will report the latest progress of optimization of Mn₃₃Ga₃₆Ge₃₁ films with various buffer layers.
The stacking structures of this work was MgO (001) substrate/buffer layer(s)/ Mn₃₃Ga₃₆Ge₃₁ (t)/MgO 2 nm/Ta 5 nm. t was varied from 100 nm to 5 nm. All the metallic layers were deposited by using an ultrahigh-vacuum magnetron sputtering system, and the MgO layer was deposited by using an electron beam evaporation system. The samples using Cr buffer layer exhibited perpendicular magnetization down to t of 50 nm. Although XRD profiles exhibited a relatively high degree of (001) orientation, diffractions from (110) planes also remained for the out-of-plane measurements of the Cr buffer samples. Samples using other buffer layers will be discussed in the presentation.