Structural and magnetic properties of ultra-thin Fe films on metal-organic chemical vapour deposited GaN(0001)

Abstract

Structural and magnetic properties of 1–10 nm thick Fe films deposited on GaN(0001) were investigated. In-situ reflecting high energy electron diffraction images indicated a α-Fe(110)/GaN(0001) growth of the 3D Volmer-Weber type. The α-Fe(110) X-ray diffraction peak showed a 1° full-width at half-maximum, indicating ≈20 nm grain sizes. A significant reduction in Fe atomic moment from its bulk value was observed for films thinner than 4 nm. Both GaN/Fe interface roughness and Fe film coercivity increased with Fe thickness, indicating a possible deterioration of Fe crystalline quality. Magnetic anisotropy was mainly uniaxial for all films while hexagonal anisotropies appeared for thicknesses higher than 3.7 nm.

Half‐Metallic Heusler Alloy/GaN Heterostructure for Semiconductor Spintronics Devices

“…A similar epitaxial relationship has been observed for epitaxial Fe/GaN(0001) heterostructures. [ 49–51 ] In the present work, the insertion of the 0.3 nm‐thick Fe layer did not lead to the 2D epitaxial growth of CFAS on GaN(0001) (Figure 1e), likely because of the surface roughness of the inserted 0.3 nm‐thick Fe layer. [ 51 ] Although the mechanism for obtaining epitaxial CFAS/GaN heterostructure has been still unclear, we have speculated the difference in the surface quality of GaN(0001) with the metal insertion affects the crystal growth of CFAS films.…”

Strong (110) Texturing and Heteroepitaxial Growth of Thin Mo Films on MoS2 Monolayer

“…As the bulk Mo has a body-centered-cubic (b.c.c.) structure, there are two possible “hexagonal-like” crystal planes: (111) and (110). , While the (111) plane of a body-centered-cubic structure is purely hexagonal in nature, the lattice mismatch between (111)-Mo and (0001)-MoS 2 is large at −40.8%, which makes this epitaxial relationship unlikely. Lower lattice mismatches are achieved on the (110)-Mo facet, where pseudohexagonal lattices of Mo have two possible epitaxial relationships, as seen in Figure (a,b): MoS 2 (0001)­[112̅0]­||Mo (110)[1̅11] and MoS 2 (0001)­[112̅0]||­Mo­(110)­[001].…”

Structure and magnetic properties of an epitaxial Fe(110)/MgO(111)/GaN(0001) heterostructure

“…Despite the insertion of the MgO barrier, the crystallographic relations of Fe and GaN remain unaltered as compared to the epitaxial Fe/GaN(0001) structures. [24][25][26] X-ray diffraction patterns were collected with a Bruker D8 Discover high-resolution X-ray diffractometer. Figure 4 shows the XRD scan of the completed heterostructure.…”

“…The coercivity value obtained for the 5 nm film was similar to the values reported previously. 26,27 In order to study the competing magnetic anisotropies and to estimate the magneto-crystalline anisotropy constants, we performed VSM measurements at different in-plane angles u for the 5 nm sample. The saturation magnetisation (M s )o ft h e Fe film, measured at RT, was found to be 1659 6 100 emu/ cm 3 , close to the bulk value of 1714 emu/cm 3 .Figure6 shows two VSM hysteresis curves taken along one of the a ½1120 and m ½1100 directions of the GaN(0001), demonstrating easy and hard axis switching, respectively.…”