*3.3.2 TEM of Zn0.94Fe0.03Ce0.03O (ZFCeO) nanoparticles*

*Electromagnetic Materials and Devices*

first-principle calculation. It is also recently reported that the RE Ce ions are responsible in support antiferromagnetic interactions in TM = Co, Fe doped ZnO [57].

The Zn0.95Co0.05O (ZCO5), Zn0.92Co0.05La0.03O (ZCLO53) and Zn0.92Co0.05Gd0.03O (ZCGO53) nanostructures were synthesized by a sol-gel process [11]. The structural information of La and Gd doped ZCO5 nanostructure using the Rietveld method for XRD pattern of wurtzite structure (space group P63mc) refined and shown in **Figure 8(a)**. The miller indices of wurtzite structure (100), (002), (101), (102) and (110), respectively, observed with diffraction angle 2θ = 31.88, 34.49, 36.34, 47.59 and 49.65° of ZnO. The XRD peak intensity of Zn0.95Co0.05O is reduced with La and Gd doping into it. This is because the ionic radii of La3+ and Gd3+ ions is much larger than TM Zn2+ and Co2+ ions, which results into lattice deformation of ZnO. Due to this, the lattice parameters such as lattice distortion, Zn–O bond length/angle and per unit cell volume are affected to induce lattice defects. The value of lattice constant, *a* = 3.252(1) Å, 3.253(2) Å and 3.255(1) Å, *c* = 5.204(1)

 = 3.37, 0.893 and 2.9, respectively, extracted for ZCO5, ZCLO53 and ZCGO53. It is also reported that the average value of particles size, D of nano-aggregation is 142 and 86 nm, respectively, for ZCLO53 and ZCGO53 [12]. The wurtzite ZnO structure and lattice defects (vacancies/interstitials) are also found with Raman study. Photoluminescence spectra have near band edge emission (shown energy band gap, Eg = 3.26 eV for ZCLO53 and for ZCGO53, Eg = 3.27 eV) and the defects/

*(a) XRD pattern of Co, La and Gd doped ZnO nanostructure. (b) TEM image of Zn0.94Fe0.03Ce0.03O nanoparticles. (c) Raman spectra of pure and low Co concentrated ZnO nanoparticles. (d) Photoluminescence* 

*(PL) of Ni, Cu, Ce substituted ZnO nanoparticles. Adopted from Refs. [10, 11, 57, 58].*

, 47.818(3) Å3

and 47.823(2) Å3

, and

*3.3.1 XRD for La, Gd substituted Zn0.95Co0.05O nanostructure*

Å, 5.218(3) Å and 5.212(3) Å, V = 47.660(1) Å3

**106**

**Figure 8.**

χ2

The DMS ZFCeO nanoparticles were synthesized by a sol-gel process [57]. **Figure 8(b)** shows the TEM image and the average particles size, D, of nanoparticles is 97 ± 4 nm. The inset of TEM is the HRTEM to show the crystalline formation and lattice spacing after doping into ZnO. It can be noted that the distorted lattice has an enhanced interplanar spacing *d* [corresponding to (101) planes] ~ 0.247 nm. For pure ZnO, the value of *d* ~ 0.237 nm. In HRTEM image, some little spots that covered the lattice fringes of spacing are also observed. This is an indication towards ferromagnetic clusters or structural inclusions formation.
