## 3 Results
### Mossbauer Results  
The Mossbauer spectra of Nd\({}_{16}\)FeFe\({}_{76-\times}\)Co\({}_{\alpha}\)B\({}_{8}\) (x = 0, 10, 20 and 25) samples, collected at RT, are shown in Figure 3. To fit these spectra, several subspectra were required, which were associated with the Nd\({}_{2}\)Fe\({}_{14}\)B, \(\alpha\)-Fe and Nd\({}_{1.1}\)Fe\({}_{4}\)B\({}_{4}\) phases. The last phase was not identified by XRD. Seven sextets were used to fit the magnetic part of the spectra, with six of them corresponding to those \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**PHASE** & \multicolumn{4}{c}{\(Nd_{2}\)Fe\({}_{14}\)B} \\ \hline
**\% Co** & **\% Phase \(\pm\) 0.3** & \(a[\AA]\pm\)0.001** & \(c[\AA]\pm\)0.001** & **Vol. [\(\AA^{3}]\pm\) 0.6** & \(\Phi\perp[\
m]\pm\)1.7** & \(\Phi[\
m]\pm\)1.7 \\ \hline
**0** & 83.8 & 8.814 & 12.210 & 948.7 & 19.3 & 25.0 \\
**10** & 68.8 & 8.799 & 12.174 & 942.7 & 32.4 & 48.3 \\
**20** & 60.5 & 8.768 & 12.138 & 933.2 & 55.0 & 94.8 \\
**25** & 63.5 & 8.762 & 12.136 & 931.9 & 44.5 & 81.0 \\ \hline
**PHASE** & \multicolumn{4}{c}{\(Nd_{1.1}\)Fe\({}_{4}\)B\({}_{4}\)} \\ \hline
**\% Co** & **\% Phase \(\pm\) 0.3** & \(a[\AA]\pm\)0.001** & \(c[\AA]\pm\)0.001** & **Vol. [\(\AA^{3}]\pm\) 0.6** & \(\Phi\perp[\
m]\pm\)1.0** & \(\Phi[\
m]\pm\)1.0 \\ \hline
**0** & 15.9 & 7.113 & 35.632 & 1802.9 & 64.7 & 5.2 \\
**10** & 31.2 & 7.096 & 35.090 & 1769.9 & 85.7 & 10.7 \\
**20** & 33.1 & 7.108 & 35.126 & 1761.1 & 52.6 & 3.8 \\
**25** & 28.7 & 7.100 & 34.993 & 1764.6 & 32.3 & 15.5 \\ \hline
**PHASE** & \multicolumn{4}{c}{\(CoO\)} \\ \hline
**\% Co** & **\% Phase \(\pm\) 0.4** & \(a[\AA]\pm\)0.001** & \(c[\AA]\pm\)0.001** & **Vol. [\(\AA^{3}]\pm\)0.2** & \(\Phi\perp[\
m]\pm\)2.0** & \(\Phi[\
m]\pm\)2.0 \\ \hline
**0** & – & – & – & – & – & – \\
**10** & – & – & – & – & – & – \\
**20** & 6.4 & 3.185 & 5.249 & 46.1 & 19.0 & 22.6 \\
**25** & 7.7 & 3.240 & 5.234 & 47.61 & 38.8 & 25.3 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Structural parameters of the Nd\({}_{16}\)FeFe\({}_{76-\times}\)Co\({}_{\alpha}\)B\({}_{8}\) samples with x = 0, 10, 20, and 25. Figure 2: (a) Lattice parameter \(a\) as a function of the Co content of the Nd\({}_{2}\)Fe\({}_{14}\)B and Nd\({}_{1.1}\)Fe\({}_{4}\)B\({}_{4}\) phases. (b) Lattice parameter \(c\) as a function of the Co content of the Nd\({}_{2}\)Fe\({}_{14}\)B and Nd\({}_{1.1}\)Fe\({}_{4}\)B\({}_{4}\) phases. reported for the hard phase (16k\({}_{1}\), 16k\({}_{2}\), 8j\({}_{1}\), 8j\({}_{2}\), 4c and 4e) and the other corresponding to the \(\alpha\)-Fe phase (s\({}^{\rm b}\)) reported by [PERSON] et al. (2015); [PERSON] et al. (2016); [PERSON] et al. (2017). As can be observed, the Mossbauer spectrum of the sample with x = 0 is typical of the Nd\({}_{2}\)Fe\({}_{14}\)B phase ([PERSON] et al., 2016). It was necessary to add a small doublet (site d) in order to obtain the best fit, and this was attributed to the paramagnetic Nd\({}_{1.1}\)Fe\({}_{4}\)B\({}_{4}\) phase ([PERSON] et al., 2016). The Mossbauer parameters, such as the hyperfine magnetic field (H\({}_{\rm hf}\)), isomer shift (IS), quadrupole splitting (QS) and area of each subspectra, are listed in Table 2. The value of line width (\(\Gamma\)) takes values of 0.33 mm/s for all sextets and 0.40 mm/s for doublets, which is attributable to the degree of disorder of the samples.