360
M. Satalkar et al.
23.2.3 Characterizations
Room temperature structural properties of annealed powders were examined by Xray diffraction (XRD) using Cu-K α radiation (wavelength ‘λ’ =0.1540562 nm) in
θ–2θ configuration (step size of 0.019 ◦ and a scanning rate of 1.14 degree/minute),
equipped by a fast counting Bruker LynxEye detector, with silicon strip technology. Elemental, quantitative analysis of surface morphology of Zn-Ni-Mg-Cu
ferrite samples was performed by energy-dispersive X-ray analysis (EDAX, INCAOXFORD) and scanning electron microscope (SEM, JEOL JSM-6390LV). Room
temperature magnetization studies were done via SQUID magnetometer (Quantum
Design MPMS-5S) with a maximum applied field (H max. ) of ± 5 tesla. The magnetic
properties, saturation magnetization (M s ), squareness ratio/reduced magnetization
(M r /M s ), and coercivity (H c ), have been elucidated from hysteresis loops.
23.3 Results and Discussions
23.3.1 Structural Properties
X-ray diffraction (XRD) patterns of Ni 2+ -doped annealed 500 ◦ C/3 h Zn 0.75−x Ni x
Mg 0.15 Cu 0.1 Fe 2 O 4 (x = 0.00–0.75) ferrite system is depicted in Fig. 23.1a. Figure
23.1b, c, respectively, illustrates the Rietveld refinement for the composition
x = 0.00 and x = 0.75, done via MAUD (Material Analysis Using Diffraction)
software [32]. XRD confirms the single-phase spinel structure (JCPDS card No. 080234), signifying the cations solubility within their individual lattice sites. Structural
parameters, experimental lattice parameter (a exp. ), Scherrer’s grain diameter (D),
hopping length at A (L A ) and B (L B ) site, and specific surface area (S) of the
studied samples, were calculated as described in [22, 33] and are specified in
Table 23.1. Observed changes in a exp. L A and L B can be accredited to difference
in ionic radii of Zn 2+ (0.060 nm) and Ni 2+ (0.055 nm) ion. Lattice parameter of
Zn 0.75−x Ni x Mg 0.15 Cu 0.1 Fe 2 O 4 ferrite system initially increases for x = 0.15 and
decreases up to x = 0.60 and again increases for x = 0.75. The value should decrease
with the substitution of larger Zn 2+ (0.060 nm) ion by smaller Ni 2+ (0.055 nm) ion.
But in present system, a exp. of Ni 2+ substituted Zn-Mg-Cu ferrite shows a nonmonotonic behavior (common in systems which are not entirely normal or inverse
[34, 35]) with increasing Ni 2+ content, violating Vegard’s law [36]. Scherrer’s grain
diameter (D) of the nano-phase synthesized particles initially increases for x = 0.15,
decreases up to x = 0.45, and thereafter again increases up to x = 0.75. Though the
synthesis was done under same conditions, the observed grain size is not same for
all Ni 2+ -doped samples. Such non-monotonic behavior of D with increasing Ni
concentration may be due to reaction condition, which initially favored the particle
growth, and when Ni content is increased further, the creation of new nuclei occurs
without any increase in particle size. At higher Ni content (0.45 < x ≤ 0.75),
M. Satalkar et al.
23.2.3 Characterizations
Room temperature structural properties of annealed powders were examined by Xray diffraction (XRD) using Cu-K α radiation (wavelength ‘λ’ =0.1540562 nm) in
θ–2θ configuration (step size of 0.019 ◦ and a scanning rate of 1.14 degree/minute),
equipped by a fast counting Bruker LynxEye detector, with silicon strip technology. Elemental, quantitative analysis of surface morphology of Zn-Ni-Mg-Cu
ferrite samples was performed by energy-dispersive X-ray analysis (EDAX, INCAOXFORD) and scanning electron microscope (SEM, JEOL JSM-6390LV). Room
temperature magnetization studies were done via SQUID magnetometer (Quantum
Design MPMS-5S) with a maximum applied field (H max. ) of ± 5 tesla. The magnetic
properties, saturation magnetization (M s ), squareness ratio/reduced magnetization
(M r /M s ), and coercivity (H c ), have been elucidated from hysteresis loops.
23.3 Results and Discussions
23.3.1 Structural Properties
X-ray diffraction (XRD) patterns of Ni 2+ -doped annealed 500 ◦ C/3 h Zn 0.75−x Ni x
Mg 0.15 Cu 0.1 Fe 2 O 4 (x = 0.00–0.75) ferrite system is depicted in Fig. 23.1a. Figure
23.1b, c, respectively, illustrates the Rietveld refinement for the composition
x = 0.00 and x = 0.75, done via MAUD (Material Analysis Using Diffraction)
software [32]. XRD confirms the single-phase spinel structure (JCPDS card No. 080234), signifying the cations solubility within their individual lattice sites. Structural
parameters, experimental lattice parameter (a exp. ), Scherrer’s grain diameter (D),
hopping length at A (L A ) and B (L B ) site, and specific surface area (S) of the
studied samples, were calculated as described in [22, 33] and are specified in
Table 23.1. Observed changes in a exp. L A and L B can be accredited to difference
in ionic radii of Zn 2+ (0.060 nm) and Ni 2+ (0.055 nm) ion. Lattice parameter of
Zn 0.75−x Ni x Mg 0.15 Cu 0.1 Fe 2 O 4 ferrite system initially increases for x = 0.15 and
decreases up to x = 0.60 and again increases for x = 0.75. The value should decrease
with the substitution of larger Zn 2+ (0.060 nm) ion by smaller Ni 2+ (0.055 nm) ion.
But in present system, a exp. of Ni 2+ substituted Zn-Mg-Cu ferrite shows a nonmonotonic behavior (common in systems which are not entirely normal or inverse
[34, 35]) with increasing Ni 2+ content, violating Vegard’s law [36]. Scherrer’s grain
diameter (D) of the nano-phase synthesized particles initially increases for x = 0.15,
decreases up to x = 0.45, and thereafter again increases up to x = 0.75. Though the
synthesis was done under same conditions, the observed grain size is not same for
all Ni 2+ -doped samples. Such non-monotonic behavior of D with increasing Ni
concentration may be due to reaction condition, which initially favored the particle
growth, and when Ni content is increased further, the creation of new nuclei occurs
without any increase in particle size. At higher Ni content (0.45 < x ≤ 0.75),