Structural and magnetic properties of FePt:SiO2 granular thin films

Abstract

Nanocomposite FePt:SiO2 films have been fabricated by annealing the as-deposited FePt/SiO2 multilayers at temperatures from 450 to 650 °C. These films consist of high-anisotropy tetragonal L10 FePt particles embedded in a SiO2 matrix. The structural and magnetic properties of these films were investigated. We have found that coercivity and grain size are highly dependent on the annealing temperature and SiO2 concentration. Films with coercivities in the range from 2 to 8 kOe and grain sizes of 10 nm or less were obtained. These films have considerable potential as high-density magnetic recording media.

Unconventional magnetic behavior of iron-oxide nanoparticles in polymeric matrices

“…Examples of current interest include magnetically hard and soft metallic alloys, 1 core-surface nanoparticles, 2 and nanocomposite films. 3,4 Recently, a new magnetic behavior has been observed at low temperature ͑5 K͒ in insulating composites based on crystalline ␥-Fe 2 O 3 ͑maghemite͒ nanoparticles dispersed in a solid polymer matrix, 5 prepared by freezing a methanol based ferrofluid of the composite: magnetic particles have been observed rotating freely in response to an applied static magnetic field ͑i.e., ''free rotor behavior''͒ after conditioning the material in a cycling magnetic field.…”

Size effect on order-disorder transition kinetics of FePt nanoparticles

“…[1][2][3][4][5][6] Spin-orbit coupling of Fe and Pt atoms in chemically ordered L1 0 -FePt phase [7] gives rise to the highest uniaxial magnetocrystalline anisotropy (MCA) energy (10 6 to 10 7 J/m 3 ) currently known, [8][9][10] allowing the alloy to remain magnetically stable under room temperature even when reduced to extremely small sizes (~3.5 nm in diameter). [11][12][13][14][15] Theoretically, successful utilization of L1 0 ordered FePt nanoparticle array will enable data storage density exceeding 1 T bit/in 2 .…”

FePt:SiO 2 granular thin film for high density magnetic recording

“…The long-range order parameter, grain size, and coercivity of the films are sensitive to the annealing temperatures, as discussed elsewhere. 9 High-density recording requires media with a coercivity of 3-4 kOe and grain size of 10 nm or less. We can adjust the coercivities and grain size of FePt:SiO 2 nanocomposite films by controlling the film composition, annealing temperature, and time.…”