xiv
2.22 e crystallic perovskite structure of BaTiO
3
: (a) Cubic lattice symmetry
of a highly symmetric perovskite structure above the Curie–Weiss
temperature > T
C
. (b) Tetragonal lattice symmetry of a distorted
(asymmetric) perovskite structure below the Curie–Weiss temperature
T < T
C
.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
2.23 Crystal and electric polarization response in the ferroelectric and
paraelectric states: (a) “tetragonal” lattice below T
C
, (b) “cubic” lattice
above T
C
, (c) hysteresis loop in the ferroelectric phase, and
(d) non-hysteretic polarization in the paraelectric phase [46]. . . . . . . . . . . . . . 54
2.24 Temperature dependence of the dielectric constant for bulk or thick-film
and thin-film BSTO [42, 44, 46]. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
2.25 Temperature dependence of the dielectric constant for the incipient
dielectric SrTiO
3
, (STO), vs. the DC bias voltage. . . . . . . . . . . . . . . . . . . . . . 55
2.26 e dielectric constant of BSTO, (Ba
X
Sr
1–X
TiO
3
), vs. temperature for
different barium contents (x). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
2.27 Dielectric constant of Ba
X
Sr
1–X
TiO
3
(BSTO) for
X D .Ba C Sr/=T i D 0:98; 0:9; 0:85, and 0.73 vs. the applied DC biasing
electric field [49, 52]. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
2.28 An orthorhombic perovskite-like crystal structure of a YBCO
superconductor: (a) oxygen-deficient YBa
2
Cu
3
O
6
and (b) fully oxygenated
YBa
2
Cu
3
O
7
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
2.29 Cross-section of a typical tunable microwave circuit exploiting ferroelectric
material features (LTCC modules) [40, 59, 60]. . . . . . . . . . . . . . . . . . . . . . . . . 59
2.30 e LTCC technology.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
2.31 Contribution of the different mechanisms to the microwave losses of
incipient ferroelectric: 1. ree-quantum, 2. Four-quantum, and 3.
Quasi-Debye mechanisms. ( D
0
=
O
). . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
2.32 Loss tangent vs. temperature for a single crystal and a thin film sample for
zero bias (E
dc
D 0) at a frequency of 10 GHz. . . . . . . . . . . . . . . . . . . . . . . . . . 66
3.1 (a) Directions of internal
N
H
i
D
N
H
0
and external
N
H
a
magnetic fields for a
thin planar ferrite sample magnetized at saturation.
(b) transversely—normal and (c) longitudinally—tangential. . . . . . . . . . . . . . . 74
3.2 Elements N
x
, N
y
, and N
z
of three different shapes of ferrite samples. . . . . . . 75
3.3 Hexagonal crystal where magnetization is oriented at an angle with
respect to the axis of symmetry. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84