Spin and orbital moments of nanoscale Fe3O4 epitaxial thin film on MgO/GaAs(100)

Abstract

Nanoscale Fe 3 O 4 epitaxial thin film has been synthesized on MgO/GaAs(100) spintronic heterostructure, and studied with X-ray magnetic circular dichroism (XMCD). We have observed a total magnetic moment (m l+s ) of (3.32±0.1)µ B /f.u., retaining 83% of the bulk value. Unquenched orbital moment (m l ) of (0.47µ B ±0.05)µ B /f.u. has been confirmed by carefully applying the sum rule. The results offer direct experimental evidence of the bulk-like total magnetic moment and a large orbital moment in the nanoscale fully epitaxial Fe 3 O 4 /MgO/GaAs(100) heterostructure, which is significant for spintronics applications. Liu et al. CITATION:

X-ray magnetic circular dichroism study of epitaxial magnetite ultrathin film on MgO(100)

“…Recently, we have reported a unquenched m orb and a well retained m spin in Fe 3 O 4 thin films grown by post-growth annealing method. 17 In this paper, we furthermore present a XMCD study of …”

Element specific spin and orbital moments of nanoscale CoFeB amorphous thin films on GaAs(100)

“…23 The orbital moment has been found to have a more important role than the spin moment in giving rise to the uniaxial magnetic anisotropy. 24,25 Hindmarch et al 22 compared the UMA of CoFeB on different substrates of AlGaAs/GaAs and AlGaAs. As shown in Table I, they found a much stronger UMA (50 Oe) on AlGaAs/GaAs substrate associated with an enhancement of the orbital to spin magnetic moments ratios m ratio of both the Fe and Co sites, and the uniaxial magnetic anisotropy field H k of the UMA was found to be proportional to the m ratio .…”

“…It is well known that orbital angular moment plays a dominant role in determining the strength of magnetocrystalline and uniaxial magnetic anisotropy 25 and XMCD technique is capable of probing directly the element specific orbital and spin moments. 24,[27][28][29] The Co 56 Fe 24 B 20 films were grown on GaAs(100) substrates. Before deposition of the CoFeB film, the substrate surface was etched and cleaned.…”

Magnetic and transport properties of epitaxial stepped Fe3O4(100) thin films

“…Magnetite, Fe 3 O 4 , is an important transition metal oxide with a nearly fully spin polarized electron band at the Fermi level (half-metallic character) and a high Curie temperature of 858 K, which make it a promising candidate for room temperature spintronic devices and applications. [14][15][16] Recently, interesting magnetic and transport properties in epitaxial Fe 3 O 4 have been reported, i.e., magnetism in nanometerthick magnetite, 17 large orbital moment in nanoscale magnetite, 18 giant magnetization in nanometer-thick magnetite, 19 a spin Seebeck effect, 20 a spin filter effect, 21 electrical fieldinduced phase transition, [22][23][24] large transversal magnetoresitance (MR), 25,26 and spin valve effect. [27][28][29] However, initial efforts in exploiting its half metallic nature in magnetic tunnel junctions (MTJ) have been far from promising.…”