Effect of ion-beam bombardment on microstructural and magnetic properties of Ni₈₀Fe₂₀/α-Fe₂O₃thin films

Abstract

Ion-beam bombardment has been established as an effective way to tune the microstructure and thus modify the magnetic anisotropy of thin film materials, leading to certain remarkable magnetic properties. In this work, we investigated a Ni 80 Fe 20 /α-Fe 2 O 3 bilayer deposited with a dual ionbeam deposition technique. Low-energy argon ion-beam bombardment during the α-Fe 2 O 3 deposition led to a decline of crystallinity and interfacial roughness of the bilayer, whereas the grain size distribution remained essentially unchanged. At low temperature, the coercivity exhibited a pronounced decrease after the bombardment, indicating that the effective uniaxial anisotropy in the ferromagnetic layer was dramatically reduced. Such reduction in uniaxial anisotropy was likely attributed to the irreversible transition in the α-Fe 2 O 3 grains caused by the ion-beam bombardment, which subsequently modified the anisotropy in the Ni 80 Fe 20 layer. The bombarded bilayer also exhibited a larger ΔM FC-ZFC compared to the unbombarded bilayer, which indicated a stronger exchange coupling between the ferromagnetic layer and the antiferromagnetic layer.

Magnetoresistive Sensor Development Roadmap (Non-Recording Applications)

“…The global vision of new MR sensor (non-recording) applications, products and services was launched out through the next 15 years and beyond. Magnetic field detection has tremendous impact on a large variety of applications and industries [8,9,[11][12][13][148][149][150][151][152], which exploit a wide range of physical phenomena and principles [7,[153][154][155][156][157][158][159][160][161][162][163][164][165][166][167]. To obtain an overview of magnetic field sensing techniques, an analysis of statistics of common magnetic sensors from 1975 to 2017 in the selected patent databases is shown in Figure 3.…”

Modification of Oxide Thin Films with Low-Energy Ion Bombardment

“…Oxides exhibit outstanding magnetic properties, and in this respect, LEIB can be employed to modify the microstructure and consequently the magnetic response of the oxide layer. Bilayers of Ni 80 Fe 20 /α-Fe 2 O 3 grown on SiO 2 exhibit, for instance, a different coercivity depending on the growth mode [35]. If ion bombardment is carried out on the α-Fe 2 O 3 layer before the growth of the Ni 80 Fe 20 film, the uniaxial anisotropy of this layer is reduced, exhibiting a lower coercivity.…”

Effects of post-deposition magnetic field annealing on magnetic properties of NiO/Co90Fe10bilayers

“…The ferromagnetic (FM)=antiferromagnetic (AF) bilayer structures have been widely investigated because understanding their mechanism is crucial for their applications in modern spintronic devices. 1,2) The microstructural and magnetic properties of the FM=AF bilayers can be altered by many techniques, such as magnetic field annealing (MFA), 3,4) ion-beam bombardment, 5,6) field cooling, 7) and so on. Among these techniques, the MFA treatment is an effective way to modify the microstructure of the bilayers, including crystallographic orientations, 8) grain sizes, 9) interlayer mixing, 10,11) etc.…”