Substrate-Orientation Dependence on Structure and Magnetic Properties of MnAs Epitaxial Layers

Abstract

Ferromagnetic MnAs layers were grown on (001), (111)A, and (111)B GaAs substrates by molecular-beam epitaxy at substrate temperatures (T s) in the range from 150 to 400° C. The crystal structure of the MnAs was NiAs type and its orientation was found to change depending on the substrate, (1101) for the (001) GaAs substrate and (0001) for the (111)A and (111)B substrates at T s between 300 and 400° C. Polar magneto-optical Kerr-effect measurement demonstrated a crystal-orientation dependence of Kerr rotation and Kerr ellipticity spectra of the MnAs epitaxial layers.

Growth and magnetic properties of zb-type MnAs films on GaAs substrates by high-temperature MBE

“…1(a) only NiAs-type MnAs (0 0 0 1) was grown on the GaAs(111)B substrate when the growth temperature was set to 200 1C. This result is similar to the reported one [17]. The RHEED pattern (not shown here) also indicates the NiAs-type MnAs growth at 200 1C.…”

“…Theoretical calculations predicted that half-metallic zb MnAs thin films grown on GaAs substrates would show a high Curie temperature (T C ) [11,12]. Even though MnAs thin films have been grown on GaAs(1 0 0) substrates or other substrates using various methods, almost all of the MnAs thin films reported so far had a hexagonal a-MnAs structure or a paramagnetic orthorhombic b-MnAs structure [13][14][15][16][17]. zb-Type…”

Correlation of structure and magnetism in GaAs with embedded Mn(Ga)As magnetic nanoclusters

“…This is the same relationship as in MnAs films grown on GaAs(111)B substrates. 8,21 In sample II, the tetrahedral clusters were found to point toward the sample surface ͓GaAs͑001͒ orientation͔, so that the tetrahedron facets are ͕111͖ planes. This finding points to a Mn segregation mechanism for cluster formation.…”

Thickness dependence of magnetic domains of MnAs films

“…After the epitaxial growth of MnAs thin films on GaAs was demonstrated [1], the MnAs films have been intensively studied in terms on the growth on various GaAs substrates, periodic elastic domains, magnetic domain structures, an application of spin injector for spin injection into semiconductor, and so on [2][3][4][5][6][7][8][9]. The two phases of MnAs coexist around room temperature depending on the thickness.…”