
39-16 Electromagnetic Variables
beenachieved. e superconducting nature of SQUID devices allows for at frequency and phase
re
sponse
fr
om
dc to GH
z
fr
equencies
. Ch
apters
5 an
d
14 in th
is
bo
ok
de
scribe
th
e
pr
inciples
be
hind
SQ
UID
de
vices
an
d
ap
plications
in
cluding
la
boratory
in
strumentation,
no
ndestructive
te
st
an
d
ev
al-
uation,
ge
ophysics,
an
d
me
dicine
.
Fi
gure
39.11 il
lustrates
th
e
ge
neral
st
ructure
of a Jo
sephson
ju
nction
an
d
th
e
vo
ltage–current
(V–I) re
lationship
. Tw
o
su
perconductors
(e.g., ni
obium)
ar
e
se
parated
by a ve
ry
th
in
in
sulating
la
yer
(e.g.,
aluminum
ox
ide)
. e th
ickness
of th
is
la
yer
is ty
pically
1 nm. Wh
en
th
e
te
mperat ...