Structure and Magnetic Properties of Aerosol Nanoparticles of Fe and Its Alloys

Figure 18

Concentration-dependent Mössbauer spectra of FeCo nanoparticles with a size of D = 10–15 nm. (a) FeCo (35%); sextet, 𝑆₁=31%, 𝐻₁=36.5 T; “sagged” line, 𝑆₂=48%; oxide doublet, 𝑆₂ = 13%; singlet of PM phase, 𝑆₄=8%; (b) FeCo (85%); two sextets: (I) 𝑆₁ = 41%, 𝐻₁=36.3 T (II), 𝑆₂=19%, 𝐻₂=33.6 T; oxide doublet,𝑆₃ = 31%; singlet, 𝑆₄ = 9%; (c) FeCo (90%); sextet 𝑆₁=36%, 𝐻₁=32.7 T; a narrow singlet, 𝑆₂=11%, a broad singlet, 𝑆₃ = 53%; (d) FeCo (85%) after heating in vacuum at 600°C for 30 min. Three sextets: (I) 𝑆₁=23%, 𝐻₁=32.8 T; (II) 𝑆₂=26%, 𝐻₂=46.3 T; (III) 𝑆₃=41%, 𝐻₂=49.4 T; doublet, 𝑆₄=10%.