Biomedical Engineering Reference
In-Depth Information
and thermal parameters was observed during rei nement and as such it
was possible to rei ne all the parameters together.
14.4
Results and Discussion
Pure perovskite phase (Figure 14.1) powders of [Pb
0.94
Sr
0.06
] [(Mn
1/3
Sb
2/3
)
0.05
(Zr
0.495
Ti
0
.
505
)
0.95
]O
3
composition were prepared by calcining the stoi-
chiometric amounts of various constituents at 800 C using a prepared
[Pb
0.94
Sr
0.06
]CO
3
and manganese antimonate precursors. h ese powders
were sintered at 1170 C to obtain the ceramic pellets of good quality and
high densities.
All the rel ection peaks of the X-ray proi le are indexed. It is obvious from
the pattern shown in Figure 14.2 that the structure is tetragonal (P4mm).
h e Pb
2+
/Sr
2+
ions occupy 1(a) sites at (0,0,z), Mn
2+
/Sb
5+
/ Zr
4+
/Ti
4+
and O
I
2-
occupy 1(b) sites at (1/2,1/2,z), and O
II
2-
occupy 2(c) sites at (1/2,0,z). For
the rei nement, the initial values of the lattice parameters were obtained
from our XRD data by least-squares method, whereas the values of the
structural parameters were taken from Noheda
et al.
[9]. In this structure,
Pb
2+
/Sr
2+
coordinates were i xed at (0,0,0) in our rei nement. Figure 14.2
also depicts the observed, calculated and dif erence proi les for the rei ned
structure. h e i t is quite good. h e rei ned structural parameters and the
positional coordinates of this composition are given in Table 14.1.
20
40
60
80
100
120
2
(degree)
Figure 14.1
XRD pattern of powder at room temperature.
