Biomedical Engineering Reference
In-Depth Information
Table 9.9
Superconducting characteristics of polymer-ceramic nanocomposites
with Mn, Co, Ni, Zn metals
Metal-monomer
complex
Y
1
Ba
2
Cu
3
O
6.98
Metal
T
c
(K)
T
f
(K)
Mass (g)
Mass (%)
Mass (g)
Mass (%)
0.293
43
0.388
57
Mn
95
87
0.396
50
0.396
50
Mn
94
85
0.90
70
0.29
30
Mn
94
84
0.518
73
0.196
27
Mn
93
85
0.90
70
0.39
30
Mn
95
85
0.416
67
0.209
33
Mn
94
83
0.552
78
0.156
22
Mn
95
85
0.325
51
0.318
49
Co
93
83
0.432
60
0.283
40
Co
92
84
0.503
70
0.228
30
Co
92
84
0.486
70
0.208
30
Ni
95
83
0.552
78
0.156
22
Zn
95
86
0.416
67
0.209
33
Zn
94
83
T
c
=93K,T
f
=78K. The SC onset increase reaches 1-3K for T
c
and more
than 5K for T
f
.
It is known from the literature that the Y
1
Ba
2
Cu
3
O
7
x
high-temperature
SC ceramic exhibits an anti-ferromagnetic transition, with a transition into
the spin glassy (vitreous) state before the desired transition into the SC state.
Presumably, anti-ferromagnetic and high-temperature SC states are co-
existent. Co, Ni and Mn are known to be anti-ferromagnetic metals which
intercalate into the interstitial layers of the ceramic, causing the three-
dimensional properties of the ceramic grains to change. This explains why
T
c
increases and the transition width decreases. This interpretation is
supported by our data on the change of valence states of Cu in polymer-
ceramic nanocomposites.
9.8
Aging of SC polymer-ceramic nanocomposites
The prevailing orientation of the crystallites in the (110) direction in the
Y
1
Ba
2
Cu
3
O
6.92
sample is practically stable over time, and is strong in
absolute value intensity line. The Y
1
Ba
2
Cu
3
O
6.97
specimen is oriented along
(006) and the absolute value of this reflex is not changed with the
progression of time. Furthermore, the Y
2
BaCuO
5
semiconductor phase is
identified as (211) - 2% in content. The texture in both of these specimens is
controlled by the relative intensities of the peaks (110), (103), (005), (014),
(113), (006), (020) and (200). As a result, the SC properties of
Y
1
Ba
2
Cu
3
O
6.97
specimens are relatively stable over time (Table 9.10), whilst
