## 3 Results and Discussion
### Dynamic Property Analysis Based on FMR Spectroscopy  
The temperature dependence of \(\alpha\) was investigated using FMR spectroscopy to verify the effects of Ta and W buffer and capping layers on the dynamic properties of the CoFeB/MgO frame. Figure 5a,b show the raw FMR spectra and the fitting of the Lorentzian function to extract the linewidth and resonance magnetic field. Black symbols and the red line represent the experimental data and the Lorentzian line shape, respectively. The FMR spectra were measured in the direction of the sample surface and parallel to the external magnetic field. \(H_{\text{r}}\) and \(\Delta H_{\text{pp}}\) values were extracted from these spectra. Figure 5 shows the normalized FMR spectra for convenience in comparing the resonance field and linewidth. Figure 5c,d show the FMR spectra of the W buffer and capping layers sample in the frequency range of 5-20 GHz at 373 K and 403 K, respectively. As the frequency increased, both the resonance field and linewidth increased. Figure 5e shows the normalized FMR spectra of the Ta buffer and capping layers sample at a fixed frequency of \(f\) = 19 GHz with increasing temperature. Both the resonance field and linewidth increased with increasing temperature. Figure 4: Variation in \(M_{\text{s}}\) for samples with Ta and W buffer and capping layers as a function of ambient temperature. Closed symbols denote the experimental data and solid lines correspond to the fitting based on Equation (1). Figure 3: Magnetic hysteresis (\(M\)–\(H\)) loops at different temperatures of (**a**) Ta buffer and capping layers sample and (**b**) W buffer and capping layers sample. We determined the value of \(\alpha\) using an expression based on the extracted linewidth [60]:  
\[\Delta H_{\text{PP}}=\frac{4\pi\alpha f}{\gamma}+\Delta H_{0} \tag{2}\]  
where \(r\) denotes the gyromagnetic ratio and \(\Delta H_{0}\) represents inhomogeneous linewidth broadening. The term \(\alpha\) was determined from the slope of Equation (2), which demonstrates a linear proportionality to frequency. As the frequency increases, the linewidth increases linearly, according to Equation (2), and as the temperature increases, the slope of the fitting line increases. Therefore, we deduced that \(\alpha\) exhibits temperature dependence [61; 62; 63]. The cause was attributable to the phenomenon of magnetization relaxation, which diminishes with a decrease in temperature [61; 62]. Additionally, we measured \(H_{\text{k}}\) as a function of temperature using the Kittel equation [64]:  
\[f=\Big{(}\frac{\gamma}{2\pi}\Big{)}\sqrt{(H_{\text{k}}+H_{\text{r}})(H_{\text{ k}}+H_{\text{r}}+4\pi M_{\text{s}})} \tag{3}\]  
As shown in Figure 5c-e, \(H_{\text{r}}\) increases as the measuring frequency increases at a constant temperature, and similarly, \(H_{\text{r}}\) increases as the measuring temperature increases at a constant frequency. According to Equation (3), the increase in \(H_{\text{r}}\) with temperature was attributable to the decrease in \(M_{\text{s}}\) with an increase in temperature [61]. Figure 6a shows that \(\alpha\) for the prepared samples exhibits a temperature dependence. As the ambient temperature increased from 306 to 443 K, the \(\alpha\) values for the samples with Ta and W buffer and capping layers increased from 0.0033 to 0.0059 and from 0.0055 to 0.0065, respectively.