610305.fig.0018
Figure 18: Concentration-dependent Mössbauer spectra of FeCo nanoparticles with a size of D = 10–15 nm. (a) FeCo (35%); sextet, 𝑆 1 = 3 1 %, 𝐻 1 = 3 6 . 5  T; “sagged” line, 𝑆 2 = 4 8 %; oxide doublet, 𝑆 2 = 13%; singlet of PM phase, 𝑆 4 = 8 %; (b) FeCo (85%); two sextets: (I) 𝑆 1 = 41%, 𝐻 1 = 3 6 . 3  T (II), 𝑆 2 = 1 9 %, 𝐻 2 = 3 3 . 6  T; oxide doublet, 𝑆 3 = 31%; singlet, 𝑆 4 = 9%; (c) FeCo (90%); sextet 𝑆 1 = 3 6 %, 𝐻 1 = 3 2 . 7  T; a narrow singlet, 𝑆 2 = 1 1 %, a broad singlet, 𝑆 3 = 53%; (d) FeCo (85%) after heating in vacuum at 600°C for 30 min. Three sextets: (I) 𝑆 1 = 2 3 %, 𝐻 1 = 3 2 . 8 T; (II) 𝑆 2 = 2 6 %, 𝐻 2 = 4 6 . 3  T; (III) 𝑆 3 = 4 1 %, 𝐻 2 = 4 9 . 4  T; doublet, 𝑆 4 = 1 0 %.