Effect of a MgO interlayer on the structural and magnetic properties of Co2Cr0.6Fe0.4Al thin films epitaxially grown on GaAs substrates

Abstract

The effect of a MgO interlayer on the structural and magnetic properties of Co 2 Cr 0.6 Fe 0.4 Al ͑CCFA͒ thin films epitaxially grown on GaAs substrates by sputtering was investigated. When the MgO interlayer thickness was 1.0 nm or less, the CCFA films were grown with a cube-on-cube relation to GaAs and no significant decrease in either the x-ray diffraction intensity or saturation magnetization was observed. In contrast, when the MgO thickness was 1.5 nm or more, the CCFA film was rotated by 45°in the ͑001͒ plane with respect to GaAs, and both the x-ray diffraction intensity and saturation magnetization decreased. All samples showed strong magnetic anisotropy, in which a uniaxial anisotropy with an easy axis of ͓110͔ GaAs or ͓1−10͔ GaAs dominated with a slight cubic anisotropy having an easy axis of ͗110͘ CCFA superimposed.

Tunneling anisotropic magnetoresistance in epitaxial CoFe/n-GaAs junctions

“…Uniaxial-type magnetic anisotropy similar to that shown in Fig. 1 has been reported in several previous studies, [11][12][13][14][15][16][17][18] in particular for Fe ͑Ref. 11͒ or Co-based Heusler alloy thin films 12-18 grown on GaAs.…”

Structural, magnetic, and electrical properties of Co2MnSi∕MgO∕n-GaAs tunnel junctions

“…For the CCFA films grown on GaAs with a MgO interlayer, however, strong uniaxial anisotropy remained even in the presence of a MgO interlayer. 12,13 The origin of this difference between the CCFA and the CMS, though, is not yet clear. Figure 3 shows the magnetization value ͑M͒ at RT as a function of t MgO .…”

“…This result also contrasted with those obtained for the CCFA/ MgO / GaAs structures in which the value of M for the CCFA film monotonically decreased as t MgO increased. 12,13 C. Electrical properties Figure 4͑a͒ shows current ͑I͒-voltage ͑V͒ characteristics of the CMS/MgO ͑3.0 nm͒ / n-GaAs junction and CMS/ n-GaAs junction at RT. The V was defined with respect to the GaAs.…”

“…12,13 The structural and magnetic properties of the CCFA thin films with MgO, however, were degraded compared with those of the CCFA without MgO. In this study, we grew CMS thin films on GaAs with a MgO interlayer, and investigated their structural and magnetic properties.…”

Electrical injection of spin-polarized electrons and electrical detection of dynamic nuclear polarization using a Heusler alloy spin source

“…Thus, the strong uniaxial-type magnetocrystalline anisotropy along the x axis direction and relatively weak shape anisotropy along the y axis direction were induced in the Co 2 MnSi/CoFe bilayer. There have been several reports that ferromagnetic thin films, including Co-based Heusler alloys, epitaxially grown on GaAs(001) substrates have an uniaxial-type anisotropy with an easy axis of either the [110] GaAs or [1][2][3][4][5][6][7][8][9][10] GaAs direction [35][36][37][38] and whose strength and direction depend on the surface reconstruction superstructures of GaAs and/or ferromagnet materials. In this study, the fabricated Co 2 MnSi/CoFe/n-GaAs junction had an easy axis of the [110] GaAs direction, which corresponded to the x axis direction.…”