Influence of annealing on microstructure and magnetic-transport of FeCo–SiO2 nanogranular films

Mössbauer study of disordering in thin sputtered FeCo–SiO2 and FeCo films

“…Thin film composite materials consisting of magnetic nanoparticles and an insulate matrix are perspective objects for the use in electromagnetic devices [1] and information industry [2]. The magnetic properties of such objects are governed by dipole-dipole interactions and exchange coupling [3] through a magnetic particle size distribution and composite structure [1,2].…”

“…The magnetic properties of such objects are governed by dipole-dipole interactions and exchange coupling [3] through a magnetic particle size distribution and composite structure [1,2]. FeCo-SiO 2 composite systems combine the highest saturation magnetization among ferromagnetic alloys of FeCo [4] and low resistivity of SiO 2 .…”

“…FeCo-SiO 2 composite systems combine the highest saturation magnetization among ferromagnetic alloys of FeCo [4] and low resistivity of SiO 2 . Two ways to prepare thin FeCo-SiO 2 films are liquid-phase (impregnation of Co (II) and Fe(III) salts into a silica film [5], co-precipitation [4] and a sol-gel route [6,7] with subsequent reduction by H 2 ), and gas-phase (RF sputtering of composite (Fe 65 Co 35 ) x (SiO 2 ) 1Àx [1] target, and co-sputtering of separate Fe x Co 1Àx and SiO 2 targets [2,[8][9][10][11]) methods. Sputtering techniques result in composites with lesser magnetic particles than in the case of the liquid-phase approach (3[2]-5 [1] nm against 10[6]-70 [4] nm); the latter results in narrower particle size distribution (5-10 nm [6] against 15-20 nm [2]).…”

Morphologies and magnetic properties of FeCo nanoparticles modulated by changing the types of ligands of Co

“…Magnetic properties of nanostructured materials are affected by their morphology and particle size. Researches on FeCo nanoparticles [3], nanoneedles [4], nanowires [5] and thin films [6,7] have proven various outcomes. Besides the interesting magnetic phenomena at the nanoscale materials, supported magnetic nanoparticles are utilized in applications such as ultra-high density storage devices [8] and nanomedicine applications [9] as the magnetic carriers [10].…”

High-frequency magnetic characteristics of Fe-Co-based nanocrystalline alloy films

“…Important progresses in high-frequency soft magnetic materials have also been attained in composite granular films, in which Ferich crystalline nanoparticles are embedded in a nonmagnetic insulator matrix, such as Al 2 O 3 [8], ZrO 2 [11], HfO 2 [12,13], SiO 2 [14] and Si 3 N 4 [15]. However, large magnetization and high resistivity can not be simultaneously achieved because high electrical resistivity always comes out in these films at the expense of the saturation magnetization.…”