Geoscience Reference
In-Depth Information
0.004
0.003
0.002
0.001
0.000
0
50
100 150
Temperature (
Κ
)
200
250
300
Figure 7.72 Thermal stability and magnetic susceptibility of Mn
2
VO(PO
4
)
2
H
2
O
[309]
.
Source: Courtesy of the Academic Press, Orlando, FL.
40
Mn
2
VO(PO
4
)
2
·H
2
O
30
20
10
0
0
50
100
150
Temperature (K)
200
250
300
Figure 7.73 Plot of the reciprocal magnetic susceptibility versus temperature for Mn
2
VO
(PO
4
)
2
H
2
O
[311]
.
Source: Courtesy of the Academic Press, Orlando, FL.
0.4168 cm
3
K/mol is the curie constant and
C
θ
52
67.5 is the Weiss temperature
5
with increasing temperature,
λ
M
first decreases rapidly but reaches a minimum at
T
B
15 K, increases up to approximately 40 K, then smoothly decreases again with
temperature (see
Figure 7.72
)
[309]
. Similarly very interesting magnetic susceptibil-
ity has been reported in several other hydrothermally prepared metal vanadyl phos-
phates
like K
2
(VO)
3
(HPO
4
)
4
,Mn
2
VO(PO
4
)
2
,H
2
O,
a-NH
4
(VO
2
)(HPO
4
),
and
CsMo
2
O
3
(PO
4
)
2
[310
313]
.
Figure 7.73
shows a plot of the reciprocal magnetic
