Structural, optical, electrical, and magnetic properties of Zn_0.7Mn_xNi_0.3−xO nanoparticles synthesized by sol–gel technique

Figures & data

Figure 1. X-ray diffraction spectra of Zn_0.7Mn_xNi_0.3−xO (x = 0.05, 0.1, 0.15, 0.2) nanoparticles calcined at 700°C.

Table 1. Compositional dependence of average crystalline size (D), SEM (D), optical band gap (E_opt), activation energy of grain boundaries (E_gb), grains (E_g), coercive field (H_c), remanent magnetization (M_r), and saturation magnetization (M_s)

Sample	D (nm)	SEM D (nm)	Eopt (eV)	Egb (eV)	Eg (eV)	Hc (Oe)	Mr (emu)	Ms(emu)
ZnO	32.30	41	3.20	0.52	0.46	0.00	0.000010	0.002
x = 0.0	29.61	40	3.14	0.64	0.41	69.64	0.000175	0.002
x = 0.05	32.32	43	2.74	0.40	0.27	39.36	0.000180	0.042
x = 0.1	35.53	45	2.83	0.47	0.05	22.99	0.000080	0.036
x = 0.15	32.30	42	2.97	0.48	0.16	48.16	0.000139	0.011
x = 0.2	39.47	47	3.04	0.77	–	37.22	0.000233	0.022

Figure 2. Scanning electron micrograph (SEM) of Zn_0.7Mn_xNi_0.3−xO (x = 0.1) sample.

Figure 3. (F(R)hυ)² vs. hυ plot for direct band gap determination of Zn_0.7Mn_xNi_0.3−xO (x = 0.05, 0.1, 0.15, 0.2) nanoparticles.

Figure 4. Variation of AC conductivity for Zn_0.7Mn_xNi_0.3−xO (Pure ZnO, x = 0.0, 0.05, 0.1, 0.15, 0.2) samples at 323 K.

Figure 5. Measured total AC conductivity (σ′) for Zn_0.7Mn_0.05Ni_0.25O composition, shown as function of frequency at eight different temperatures.

Note: The solid lines in the figure are the best fits obtained from fitting of experimental data with Jonscher’s power law.

Figure 6. Plot of frequency exponent n with temperature for Zn_0.7Mn_xNi_0.3−xO (x = 0.05, 0.1, 0.15, 0.2) samples at low frequency dispersion region.

Figure 7. Arrhenius plots of DC conductivity (σ_dc) for Zn_0.7Mn_xNi_0.3−xO (x = 0.05, 0.1, 0.15, 0.2) samples.

Figure 8. Field-dependent magnetization at room temperature Zn_0.7Mn_xNi_0.3−xO (Pure ZnO, x = 0.0, 0.05, 0.1, 0.15, 0.2) samples.

Note: Inset shows the enlarged figure for x = 0.2.