## 3 Results and Discussion
### Magnetization Analysis
Owing to this, the particles present on the surface contributed more to the direction of the magnetic moments pointing away from the easy magnetization direction of Ni, and thereby reduce net saturation magnetization. In the same way, the largest saturation magnetization value (as compared with the other samples) was found for the Ni-Non-Magnetic sample, despite its surface roughness, which may be associated with the absence of an external magnetic field during synthesis [13]. Furthermore, the magnetocrystalline anisotropy present in the Ni wires was estimated using the law-of-approach-to-saturation (LAS) procedure, in stronger magnetic fields, at a temperature of 50 K. The law-of-approach procedure can be described by the following equation [14; 15]:  
\[\mathrm{M}=\mathrm{Ms}\left[1-\frac{\mathbf{b}}{\mathbf{H}^{2}}\right] \tag{1}\]  
where M is the magnetic field-dependent (H) magnetization, Ms is the saturation magnetization and b is the anisotropy term. The anisotropy constant (K), which gives information about the strength of the magnetic anisotropy, is obtained using the value of b in the following Equation (2) [14; 15]:  
\[\mathrm{b}=\frac{8}{105}\frac{\mathrm{K}^{2}}{\mu_{0}^{2}\mathrm{M}_{8}^{2}} \tag{2}\]  
The law of approach fit of all the samples at temperatures of 300 K and 50 K is displayed in Figure 5. The insets of the respective figures show the enlarged portion of the fitted curve at higher magnetic fields (above 25,000 Oe). A very small separation was observed in the ranges of \(\sim\)0.05-0.08 emu/g at 300 K and \(\sim\)0.1-0.3 emu/g at 50 K. The values of the anisotropy constants are displayed in Table 1. We observed that the values of K increased as a consequence of a magnetic field applied externally during synthesis. The magnetic anisotropy constant provides a measurement of the anisotropic force [11]. The magnetic moments of individual particles on the surface are aligned away from the direction of easy magnetization of Ni <111> during the course of synthesis, therefore, significant amount of work needs to be done by the crystal increasing its magnetic anisotropy. Enhanced anisotropy in magnetically assembled nanowires has previously been reported by [PERSON] et al. [16]. It is noticeable that, in the present case, the maximum value of K was obtained for the Ni-Ring sample, which is attributable to its increased surface roughness. Further, an increase in magnetic anisotropy can be observed in the coercivity of the samples. Figure 6 shows the increase in coercivity of the samples when the temperature was reduced from 300 K (\(\sim\)130 Oe) to 50 K (\(\sim\)200 Oe). Therefore, the shape of the externally applied magnetic field during synthesis contributed to the formation of Ni-wires with relatively lower diameters and enhanced surface attributes, which further modified the observed magnetic anisotropies. Figure 5: Law-of-approach fit of Ni-Non-Magnetic wires; Ni-Double wires; Ni-Single wires; Ni-Ring wires, using MH hysteresis curves, measured at 300 K and 50 K. The insets of the respective figures show the zoom of fit of LAS at high fields (>25,000 Oe). The experimental and fitted curve show a separation in the ranges of \(\sim\)0.05–0.08 emu/g at 300 K and \(\sim\)0.1–0.3 emu/g at 50 K.  
Figure 6: Comparison of MH hysteresis curves of each sample at temperatures of 300 K and 50 K.