# Magnetic Nanoparticles as Mediators for Magnetic Hyperthermia Therapy Applications: A Status Review
## 3 Results and Discussion
### Thermogravimetric Analysis and Modified Thermogravimetric Analysis
In Figure 11, the \(T_{\rm C}\) of the samples follows each other, namely sample A has a \(T_{\rm C}\) of 63 \({}^{\circ}\)C, sample B has a \(T_{\rm C}\) of 54 \({}^{\circ}\)C, and sample C has a \(T_{\rm C}\) of 51 \({}^{\circ}\)C. As the Ni content increases, so does the \(T_{\rm C}\). Figure 12 shows the first derivative of TM curves of Cu\({}_{1-x}\)Ni\({}_{x}\) alloys (ball-milling), the maximum of which is attributed to the corresponding \(T_{\rm C}\)[55]. The TM curves have a slightly asymmetric shape, indicating inhomogeneity in the composition and size of the MNPs. Again, \(T_{\rm C}\) increases with the increasing Ni content, so we can change the composition according to the desired \(T_{\rm C}\). \(T_{\rm C}\) in the therapeutic range around 45 \({}^{\circ}\)C shows sample C with composition Cu\({}_{27.5}\)Ni\({}_{72.5}\). Figure 13 shows the DTMC of Cr\({}_{x}\)Ni\({}_{1-x}\) alloys (ball-milling) [107]. The \(T_{\rm C}\) of the samples was determined by the temperature, which belongs to 50% of the peaks of the demagnetization curves. The samples are heterogeneous in composition, as evidenced by asymmetric TM curves. Figure 13 also clearly shows how the \(T_{\rm C}\) increases with increasing Ni content in each sample. Sample S1, which has the highest Ni content, also has the highest \(T_{\rm C}\), and conversely, S7 has the lowest \(T_{\rm C}\) and the lowest Ni content. The \(T_{\rm C}\) for the synthesized (Mg, Ti)-ferrite MNPs, thermally homogenized NiCu MNPs, and NiCu and NiCr ball-milled MNPs were measured and are shown in Table 2.  
The (Mg, Ti)-ferrite MNPs were synthesized by the coprecipitation method, thermally homogenized Ni\({}_{0.725}\)Cu\({}_{0.275}\) were synthesized by a microemulsion method, and Ni\({}_{67.5}\)Cu\({}_{32.5}\), Ni\({}_{62.5}\)Cu\({}_{37.5}\), and Ni\({}_{60}\)Cu\({}_{40}\) in a silica matrix were synthesized by a sol-gel method. The NiCu (B-F) (Figure 12) and NiCr (S1-S7) (Figure 13) MNPs were synthesized by mechanical milling. The transition from a ferrimagnetic to a paramagnetic state at \(T_{\rm C}\) depends on energy exchange. The (Mg, Ti)-ferrite MNPs (sample B, x = 0.37) exhibit \(T_{\rm C}\) close to 46 \({}^{\circ}\)C and thus meet the therapeutic requirement. To obtain the desired \(T_{\rm C}\), MNPs with composition Cu\({}_{27.5}\)Ni\({}_{72.5}\) (microemulsion technique) were thermally homogenized at 750 \({}^{\circ}\)C for 5 h in a reducing Ar/H\({}_{2}\) atmosphere. The homogenized MNPs have \(T_{\rm C}\) at 45 \({}^{\circ}\)C. For the MNPs (Ni\({}_{67.5}\)Cu\({}_{32.5}\) (A), Ni\({}_{62.5}\)Cu\({}_{37.5}\) (B), Ni\({}_{60}\)Cu\({}_{40}\) (C)) synthesized by the sol-gel method, the determined \(T_{\rm C}\) agreed with the selected nominal composition. In the case of mechanical milling, the measurements showed that the \(T_{\rm C}\) of MNPs could be adjusted by changing the molar ratio of Cu/Ni. \(T_{\rm C}\) increased with increasing nickel content. Similar \begin{table}
\begin{tabular}{c c c c} \hline
**Sample Name** & **Figure** & \(T_{\rm C}\) [\({}^{\circ}\)C] & **References** \\ \hline (Mg, Ti)-ferrite (x = 0.37) & Figure 9b & 46 & [26] \\ Ni\({}_{0.725}\)Cu\({}_{0.275}\) & Figure 10 & 45 & [41] \\ Ni\({}_{67.5}\)Cu\({}_{32.5}\) (A) & Figure 11 & 63 & \\ Ni\({}_{62.5}\)Cu\({}_{37.5}\) (B) & Figure 11 & 54 & [103] \\ Ni\({}_{60}\)Cu\({}_{40}\) (C) & Figure 11 & 51 & \\ Cu\({}_{30}\)Ni\({}_{70}\) (B) & Figure 12 & 24 & \\ Cu\({}_{27.5}\)Ni\({}_{72.5}\) (C) & Figure 12 & 45 & \\ Cu\({}_{27.5}\)Ni\({}_{73}\) (D) & Figure 12 & 53 & [55] \\ Cu\({}_{25}\)Ni\({}_{75}\) (E) & Figure 12 & 137 & \\ Cu\({}_{20}\)Ni\({}_{80}\) (F) & Figure 12 & 174 & \\ Cr\({}_{10}\)Ni\({}_{90}\) (S1) & Figure 13 & 340 & \\ Cr\({}_{15}\)Ni\({}_{85}\) (S2) & Figure 13 & 262 & \\ Cr\({}_{20}\)Ni\({}_{85}\) (S3) & Figure 13 & 138 & \\ Cr\({}_{20}\)Ni\({}_{74}\) (S4) & Figure 13 & 69 & [107] \\ Cr\({}_{27.5}\)Ni\({}_{73}\) (S5) & Figure 13 & 52 & \\ Cr\({}_{28}\)Ni\({}_{72}\) (S6) & Figure 13 & 44 & \\ Cr\({}_{29}\)Ni\({}_{71}\) (S7) & Figure 13 & 43 & \\ \hline \end{tabular}
\end{table}