Research Article Hydrostatic Parameters and Domain Effects in Novel 2-2 Composites Based on PZN-0.12PT Single Crystals

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1 Sart Materials Research Volue 2, Article ID 7364, pages doi:.55/2/7364 Research Article Hydrostatic Paraeters and Doain Effects in Novel 2-2 Coposites Based on PZN-.2PT Single Crystals Vitaly Yu. Topolov, Sergei V. Glushanin, 2 and Alexander A. Panich 2 Departent of Physics, Southern Federal University, 5 Zorge Street, Rostov-on-Don 3449, Russia 2 Scientific Design & Technology Institute Piezopribor, Southern Federal University, Milchakov Street, Rostov-on-Don 3449, Russia Correspondence should be addressed to Vitaly Yu. Topolov, vutopolov@sfedu.ru Received 8 October 2; Accepted 26 January 2 Acadeic Editor: Zhifei Shi Copyright 2 Vitaly Yu. Topolov et al. This is an open access article distributed under the Creative Coons Attribution License, which perits unrestricted use, distribution, and reproduction in any ediu, provided the original work is properly cited. A novel.88pb(zn /3 Nb 2/3 )O 3 -.2PbTiO 3 crystal/polyer coposite with 2-2 connectivity is studied at variable orientations of spontaneous polarisation vector of the crystal coponent. Orientation and volue-fraction dependences of the hydrostatic piezoelectric coefficients dh, eh,andgh and hydrostatic electroechanical coupling factor kh are related to the iportant role of the piezoelectric and elastic anisotropy of single-doain layers of the 2-2 coposite. The record value of eh 77 C/2 near the absolute-iniu point and the correlation between the hydrostatic (eh ) and piezoelectric (e3j)coefficients and between the hydrostatic (gh ) and piezoelectric (g3j)coefficients are first established. This discovery is of value for hydrostatic and piezotechnical applications. The hydrostatic perforance of the coposite based on the single-doain.88pb(zn /3 Nb 2/3 )O 3 -.2PbTiO 3 crystal is copared to the perforance of the 2 2 coposites based on either the sae polydoain crystal or the related single-doain crystal.. Introduction The polarisation orientation effectinadvancedpiezo-active coposites based on relaxor-ferroelectric single crystals (SCs) of ( x)pb(zn /3 Nb 2/3 )O 3 -xpbtio 3 (PZN-xPT) [ 3] and( y)pb(mg /3 Nb 2/3 )O 3 -ypbtio 3 (PMN-yPT) [3, 4] opens up new possibilities of the variation of effective paraeters of the coposites that are of value for odern hydroacoustic and piezotechnical applications. The anisotropic SC coponent with large piezoelectric coefficients (e.g., d () 3j 3 pc/n, hereafter we use superscript () to denote electroechanical constants of the SC coponent) [5, 6] plays an iportant role in foring the piezoelectric effect of the coposite and its hydrostatic piezoelectric response, as shown in recent papers on the 2-2 [, 3, 4] and -3 [2] SC/polyer coposites. The 2-2 parallel-connected coposite based on the single-doain PMN-.PT SC [4] is an exaple of a piezoelectric aterial whereby large hydrostatic piezoelectric coefficients are achieved at specific orientations of the crystallographic axes and SC volue fraction. As is known, the cheical coposition of PMN-.PT is located near the orphotropic phase boundary, and the PMN-.PT SC in the single-doain state is described by 3 syetry at roo teperature [7]. Along with electroechanical constants of PMN-.PT, there are coplete sets of rooteperature electroechanical constants (Table )easured on the single-doain PMN-.42PT [5] and PZN-.2PT [8] SCs with 4 syetry. We see the difference between of PMN-.42PT and PZN-.2PT SCs, for which the order of agnitude of d () ij reains 2 pc/n (Table ). We note that the single-doain PZN-.2PT SC exhibits a distinctive elastic anisotropy in coparison to that of the single-doain PMN-.42PT SC: according to data fro Table,ratios the piezoelectric coefficients d () ij s (),E s (),E = 2.7, s (),E s (),E 3 =. ()

2 2 Sart Materials Research Table : Elastic copliances s (n),e ab (in 2 Pa ), piezoelectric coefficients d (n) ij single-doain SC and polyer coponents at roo teperature. (in pc/n), and relative dielectric perittivity ε (n),σ pp /ε of Coponents s (n),e s (n),e 2 s (n),e 3 s (n),e s (n),e 44 s (n),e 66 PZN-.2PT SC [8] PMN-.42PT SC [5] Polyurethane [] Coponents d (n) 3 d (n) d (n) 5 ε (n),σ /ε ε (n),σ /ε PZN-.2PT SC [8] PMN-.42PT SC [5] Polyurethane [] are valid for PZN-.2PT. At the sae tie, the singledoain SCs are characterised by the alost equal anisotropy of d () 3j :asfollowsfrotable, d () d () 3 d () d () 3 = 2.6(PZN-.2PT), = 2.86(PMN-.42PT). The distinctions shown in () could influence the piezoelectric effect and hydrostatic response of the coposite, and such an effect has not been considered in detail in earlier studies. In this work, we first study the doain effects concerned with the polarisation orientation and the hydrostatic response of the 2-2 SC/polyer coposite in a wide volue fraction and orientation ranges. The ai of the present paper is to show the role of the doain effects and the electroechanical properties of SCs in developing a considerable hydrostatic response of the 2-2 coposite (with either single-doain or polydoain layers). Below we discuss soe advantages concerned with the hydrostatic piezoelectric coefficients of the coposite based on the single-doain PZN-.2PT SC. 2. Structure and Effective Electroechanical Properties of the 2-2 Coposite OX 3.We consider rotations of the P () s vector around one of the coordinate axes OX or OX 2 (see insets and 2 in Figure ), and all the SC layers in the coposite saple have the sae orientation of P () s.thus,asysteofsccutswithafixed orientation of the crystallographic axes X, Y, andz is to be It is assued that the coposite represents a syste of the parallel-connected SC and polyer layers which for the regular lainar structure (Figure ) with 2-2 connectivity (in ters of [9]). The crystallographic axes X, Y, andz of the single-doain SC in the initial state (α = or β = ; see insets and 2 in Figure ) are parallel to the following perovskite unit-cell directions: X [] OX, Y [] OX 2,andZ [] OX 3. In this case, the spontaneous polarization vector in each SC layer is P () s (2) prepared before anufacturing the 2-2 coposite saple. The orientation of the crystallographic axes in the aligned cuts can be checked by eans of X-ray technique, and the further poling procedure is assued to be perfored at the fixed orientation of the coposite saple as a whole. The single-doain state of the SC layers (cuts) in the saple can be stabilised under bias. In a polydoain SC layer, the rotation of the effective spontaneous polarisation vector P (,polyd) s = d P s, +( d )P s,2 in the (X 2 OX 3 ) plane is caused by changes in the volue fraction d of the lainar 9 doains (inset 3 in Figure ), and these changes can be caused by an external electric field that is initially applied to the SC layers. The effective electroechanical properties of the 2-2 coposite are studied within the fraework of the atrix approach [] that is applied to coposite aterials with planar icrogeoetry. The 9 9 atrix of the effective properties of the coposite in the rectangular co-ordinate syste (X X 2 X 3 ) C = s E d t (3) d ε σ is written in ters of s E (6 6 atrix of elastic copliances at constant electric field), d (3 6atrix of piezoelectric charge coefficients), and ε σ (3 3atrix of dielectric perittivities easured at constant stress), where superscript t denotes the transposed atrix. The C atrix fro (3) is deterined fro averaging the electroechanical properties of coponents on the volue fraction and is given by C = [ C () M + C (2) ( ) ] [ M + I ( )], where C () and C (2) are atrices of the electroechanical properties of SC and polyer, respectively, M is concerned with the electric and echanical boundary conditions [] at interfaces x = const (Figure ), and I is the identity 9 9 atrix. Eleents of the C () atrix are written taking into account the orientation of P () s in the single-doain SC layer (insets and 2 in Figure ) or the volue fraction d of the 9 doains (inset 3 in Figure ). (4)

3 Sart Materials Research 3 X 3 Polyer, volue fraction Single crystal, volue fraction X 2 X X 3 d X 3 α X 3 X 2 X 3 β X 3 d P () P () s s X X 2 X 2 X X X 2 = X 2 = X X 2 3 Figure : Scheatic of the 2-2 parallel-connected SC/polyer coposite. (X X 2 X 3 ) is the rectangular co-ordinate syste of the coposite saple α and β are angles of rotation of the spontaneous polarisation vector P () s OX 3 of the single-doain SC layer around the OX axis (inset ) or around the OX 2 axis (inset 2). In inset 3 the 9 doain structure in the SC layer is scheatically shown, where d and d are volue fractions of the 9 doains in the SC layer, and their spontaneous polarisation vectors are shown with arrows. In case of the single-doain SC layer, the eleents of C () are represented in the tensor for as ε np (),σ = r nk r pl (ε (),σ kl ) T, d () ifg = r it r fu r gv (d tuv) () T, and s (),E pqvw = r pc r ql r vh r wn (s (),E clhn ) T,wherer nk is the eleent of the atrix that describes the rotation of the P () s vector and the coordinate axes, and subscript T eans that the electroechanical constant is given in the ain crystallographic axes, that is, taken fro Table. The aforeentioned rotation is shown in either inset in Figure (then r nk is represented in the general for as r nk = r nk (α)) or inset 2 in Figure (then in the general for r nk = r nk (β)). In the case of a polydoain SC layer (inset 3 in Figure ), the rotation of the co-ordinate axes by α = ±45 in the adjacent doains is to be taken into account in the atrix eleents r nk, r pl, and so forth. The effective electroechanical properties of the polydoain SC layer in the co-ordinate syste (X X 2 X 3 ) are deterined by analogy with (4) C () [ C = (d) Md d + C (d2) ( d ) ] [ M d d + I ( d )], where C (d) and C (d2) are atrices of electroechanical constants of the 9 doains with the volue fractions d and d,respectively,and M d is the atrix concerned (5) with the boundary conditions [] for elastic and electric fields at the doain wall x 3 = const. The atrix fro (5) is represented in the general for by C () s (),E s (),E 2 s (),E 3 s (),E 4 d () 2 d () 3 s (),E 2 s (),E 22 s (),E 23 s (),E 24 d () 22 d () 32 s (),E 3 s (),E 23 s (),E s (),E 34 d () 23 d () s (),E 4 s (),E 24 s (),E 34 s (),E 44 d () 24 d () 34 = s (),E 55 s (),E 56 d () 5 s (),E 56 s (),E 66 d () 6 d () 5 d () 6 ε (),σ d () 2 d () 22 d () 23 d () 24 ε (),σ 22 ε (),σ 23 d () 3 d () 32 d () d () 34 ε (),σ 23 ε (),σ. (6) It should be added that the electroechanical properties of the polydoain PZN-.2PT SC were also calculated in [8].

4 4 Sart Materials Research The M atrix fro (4) is deterined [] with due regard for the boundary conditions at the layer interfaces x = const as follows: M = W W 2,where W n s (n),e 2 s (n),e 22 s (n),e 23 s (n),e 24 s (n),e 25 s (n),e 26 d (n) 2 d (n) 22 d (n) 32 s (n),e 3 s (n),e 23 s (n),e s (n),e 34 s (n),e 35 s (n),e 36 d (n) 3 d (n) 23 d (n) s (n),e 4 s (n),e 24 s (n),e 34 s (n),e 44 s (n),e 45 s (n),e 46 d (n) 4 d (n) 24 d (n) 34, = d (n) d (n) 2 d (n) 3 d (n) 4 d (n) 5 d (n) 6 ε (n),σ ε (n),σ 2 ε (n),σ 3 (7) n = is related to SC, and n = 2 is related to polyer. The effective electroechanical properties of the coposite ( C fro (4)) and the polydoain layer ( C () fro (5)) are deterined on an assuption that the wavelengths of acoustic waves propagated are considerably longer than the thickness of each layer in the coposite saple (Figure ), and the thickness of each doain (see inset 3 in Figure ) is uch less than the height of the polydoain layer. Based on atrix eleents of C fro (4), we study the volue fraction and orientation dependences of the hydrostatic piezoelectric coefficients d h = d 3 + d 32 + d, = g 3 + g 32 + g, = e 3 + e 32 + e, and hydrostatic electroechanical coupling factor of the coposite kh = dh sh Eε σ (8). (9) The piezoelectric coefficients gij fro (8) are deterined fro the atrix g = d ε σ the piezoelectric coefficients eij fro (8) are deterined fro the atrix e = d s E. Hydrostatic copliance sh E of the coposite at E = const (see (9)) is defined as follows: sh E = 3 3b= a= sab E. The hydrostatic paraeters Φ h fro (8) and(9) characterise the perforance of the coposite saple (Figure ) with electrodes that are parallel to the (X OX 2 ) plane. The effective electroechanical properties of the polydoain SC layer (inset 3, Figure ), the coposite as a whole (see (4)), and its hydrostatic paraeters (see (8) and (9)) are calculated using the full sets of experiental electroechanicalconstants frotable. 3. Hydrostatic Paraeters and Advantages Exaples of the calculated volue-fraction and orientation dependences of the hydrostatic paraeters Φ h of the coposite based on the single-doain PZN-.2PT SC are shown in Figures 2 and 3. The presence of SC with 4 syetry and polyer with syetry enables us to establish the periodic dependence of the hydrostatic paraeters on the rotation angles α and β. For any value of fro the range <<, the equalities Φ h (, α) = Φ h (, 8 α) andφ h (, β) = Φ h (, β) hold,where α<9 and β<9. Changes in the orientation of the P s () vector of the SC layer in the (X 2 OX 3 ) plane (inset in Figure ) ean changes in projections of P () s on the OX 2 and OX 3 axes, along which both the coponents of the coposite are distributed continuously. Such a ode of rotation of the P () s vector leads to a relatively sooth dependence of the hydrostatic paraeters Φ h on α (Figure 2). The hydrostatic piezoelectric coefficient dh of the coposite (Figure 2(a)) reains less than d () h of the single-doain SC. A cobination of the piezoelectric (dij) and dielectric (ε σ pp)properties gives rise to the pronounced axia of gh at α = const (Figure 2(b)) however, these axia take place at a sall volue fraction. In(Figure 2(b)), we oit the voluefraction range. < < where gh onotonically decreases at α = const. Cobining the piezoelectric (dij)and elastic (sab E ) properties, one can attain the nononotonic volue-fraction behaviour of the hydrostatic piezoelectric coefficient eh (Figure 2(c)) however,valuesofe h near the local axiu points are relatively sall. The coplicated shape of the surface of kh (, α) (Figure 2(d)) isaresultof the active influence of the dielectric properties at <<. and of the elastic properties at.4 <<.9. As follows fro the coparison of the kh (, α)andd h (, α)dependences, there is a correlation between the in certain ranges of and α. It should be noted that this correlation stes fro (9) and is concerned with the relatively sooth dependence of sh E and ε σ on and α. The related coposite based on the polydoain SC (see inset 3 in Figure ) is characterised by the hydrostatic paraeters varying in the fairly narrow ranges (Table 2). The polydoain SC layers have fixed orientations and volue fractions ( d and d )ofthe9 doains over the whole coposite saple, and a change in d eans a rotation of the effective spontaneous polarisation vector (, polyd) P s in the (X 2 OX 3 ) plane. As in the previous case of the single-doain SC layer, this rotation does not lead to considerable hydrostatic paraeters. In our evaluations, the 9 doain walls of the polydoain SC layer are assued to be otionless. A contribution fro the 9 doain-wall displaceents [2] provides a contribution into electroechanical constants of SC. Our estiations show that this doain-wall contribution ight give rise to

5 Sart Materials Research d h α (deg) α (deg) (a) (b) k h α (deg) α (deg) (c) (d) Figure 2: Hydrostatic piezoelectric coefficients (a) (c) and electroechanical coupling factor (d) of the PZN-.2PT SC/polyurethane coposite at the rotation of the spontaneous polarisation vector P () s of the single-doain SC layer around the OX axis (see inset in Figure ): (a) dh (in pc/n), (b) gh (in V /N), (c) eh (in C/ 2 ), and (d) kh. increasing the upper bounds on Φ h (Table 2) by about.5 2 ties. Varying the angle β eans the crossing of the spontaneous polarisation vector P () s of the single-doain SC layer and the interface x = const (see inset 2 in Figure ). This ode of rotation of P () s becoes favourable to achieve large values of hydrostatic paraeters Φ h (, β) (Figure 3). In addition to the aforeentioned cobination of the electroechanical properties, the anisotropy of elastic copliances s (),E ab of SC leads to increasing Φ h in different volue-fraction ranges. Of particular interest is the hydrostatic piezoelectric coefficient eh (, β) (Figure 3(c)) with the deep absolute iniu. Recently [4], absolute in eh = 44.4C/2 was found for the 2-2 PMN-.PT SC/polyvinylidene fluoride coposite with the singledoain SC and piezo-active polyer layers. Distinctions between PMN-.PT and PZN-.2PT (both SCs in the single-doain state) are associated with both syetry [7, 8] and anisotropy of the electroechanical properties. As follows fro experiental data on single-doain PMN-.PT SCs with 3 syetry [7], the ratios s (),E /s (),E 3 =., s (),E /s (),E = 4.68, and d () 22 /d () = 7.5 hold in the ain crystallographic axes. The above circustances are to be taken into account when coparing the coposite perforance. Undoubtedly, values of eh 77 C/2 (Figure 3(c)) enable us to regard the studied 2-2 coposite as an outstanding piezoelectric aterial for hydroacoustic applications. To the best of our knowledge, in various ferroelectric ceraic/polyer coposites [], the typical eh values do not exceed 4 C/ 2,andvaluesof C/2 are peculiar to conventional poled ferroelectric ceraics at roo teperature [, 3]. Our coparison of the perforance of the coposites based on single-doain SCs of PZN-.2PT and PMN-.42PT SCs (Table 3) suggests that the ain difference between the hydrostatic paraeters of these coposites is associated with the piezoelectric coefficients of the SCs

6 6 Sart Materials Research d h β (deg) β (deg) (a) (b) k h β (deg) β (deg) (c) (d) Figure 3: Hydrostatic piezoelectric coefficients (a) (c) and electroechanical coupling factor (d) of the PZN-.2PT SC/polyurethane coposite at the rotation of the spontaneous polarisation vector P () s of the single-doain SC layer around the OX 2 axis (see inset 2 in Figure ): (a) dh (in pc/n), (b) gh (in V /N), (c) eh (in C/ 2 ), and (d) kh. Table 2: Lower and upper bounds on hydrostatic paraeters Φ h (, d ) of the PZN-.2PT SC/polyurethane coposite with polydoain SC layers (see inset 3 in Figure )at<<and d = const. Φ h d =.and d =.9 d =.3and d =.7 d =.5 dh (in pc/n) <dh < 89.8 <dh < 89.8 <dh < 89.8 (in V /N) <gh <.6 <gh < 4.68 <gh <.89 eh (in C/ 2 ).86 <eh <.763 <eh < 7.8 <eh <.5 kh <kh <.5 <kh <.5 <kh <.5 (Table ). In addition, the hydrostatic piezoelectric coefficient gh (see Table 3 and Figures 2(b) and 3(b)) atsall volue fractions ( < <.) strongly depends on the dielectric properties of coponents, while the hydrostatic piezoelectric coefficient eh ainly depends on the anisotropy of the elastic properties of SC. It is clear that the anisotropy of elastic copliances s (),E ab of the single-doain PMN-.42PT SC is less pronounced (Table ) and therefore do not lead to the very large eh values in the coposite based on this SC. As for the extree values of gh, they are achieved at sall volue fractions and are of the sae order of agnitude as those studied in earlier papers [, 3, 4, ]. We also reveal an interesting correlation between the volue-fraction dependences of the hydrostatic piezoelectric coefficients and the piezoelectric coefficients that contribute to the hydrostatic response of the coposite based on

7 Sart Materials Research 7 Table 3: Extree values of hydrostatic paraeters Φ h (, β) of 2-2 coposites with single-doain SC layers (see inset 2 in Figure ) at << and β 9. Paraeter d h k h Single-doain PZN-.2PT SC/polyurethane coposite Single-doain PMN-.42PT SC/polyurethane coposite Absolute inia Absolute axia Absolute inia Absolute axia 6 pc/n at =.9 24 pc/n at = pc/n at =.8 3 pc/n at =.968 and β = 78 and β = 72 and β = 78 and β = V /N at = 25 V /N at = V /N at =.5 97 V /N at =.7.5 and β = 7 and β = and β = 7 and β = 77.2 C/ 2 at = C/ 2 at = C/ 2 at = C/ 2 at =.93 and β = 83 and β = 35 and β = 79 and β =.237 at =.2 and β = 74 a. at = at =.63 and β = 74 and β = a Thelargestvalueofkh corresponds to SC ( = ). β = 8 β = e 3j, e h 3 4 e 3j, e h e 3 e 32 e e 3 e 32 e (a) (b) β = 86 e 3j, e h e 3 e 32 e (c) Figure 4: Correlation between piezoelectric coefficients e3j and eh (in C/ 2 ) of the PZN-.2PT SC/polyurethane coposite near absolute in eh. The spontaneous polarisation vector P () s of the single-doain SC layer is oriented as shown in inset 2 in Figure, the rotation angle β = 8 (a), 83 (b) and 86 (c).

8 8 Sart Materials Research 3 β = 69 3 β = g 3j, g h g 3j, g h g 3 g 32 g g 3 g 32 g (a) (b) 3 β = 73 2 g 3j, g h g 3 g 32 g (c) Figure 5: Correlation between piezoelectric coefficients g3j and gh (in V /N) of the PZN.2PT SC/polyurethane coposite near absolute in gh. The spontaneous polarisation vector P () s of the single-doain SC layer is oriented as shown in inset 2 in Figure, the rotation angle β = 69 (a), 7 (b) and 73 (c). PZN-.2PT SC (see (8) and Figures 4 and 5). Graphs in Figure 4 show that, near the absolute iniu of eh, the piezoelectric coefficients e3j fro (8) obey conditions e32 e, e e 3, () that is, the presence of interfaces x = const weakens the electroechanical interaction between the SC layers (Figure ) and strongly influences the anisotropy of e3j. Contrary to e3j fro Figure 4, the piezoelectric coefficients g3j fro Figure 5 obey conditions g3 g32, g g h. () In our opinion, the distinctions between conditions ()and () are associated with the different volue-fraction ranges of validity (e.g., large values for e3j and sall values for g3j) and with the cobination of the properties in the 2-2 parallel-connected coposite. In case of e3j, the cobination of the piezoelectric and elastic properties plays the leading role, whereas behaviour of g3j is accounted for by the cobination of the piezoelectric and dielectric properties. Graphs in Figure 5 suggest that large gh values can be attained at volue fractions of SC.4.7, and this range is to be taken into consideration when anufacturing the coposite saple with high piezoelectric sensitivity. Our analysis of behaviour of the piezoelectric coefficients near the absolute axia (Figures 4 and 5) enables us to conclude

9 Sart Materials Research 9 that not only the elastic and dielectric anisotropy, but also the parallel interfaces x = const in the coposite saple influence validity of conditions () and() in certain volue-fraction and orientation ranges. 4. Conclusion In this paper, we first studied features of the hydrostatic piezoelectric response of the novel 2-2 PZN-.2PT SC/polyurethane coposite with parallel-connected layers. The considerable hydrostatic paraeters and the anisotropy of the piezoelectric coefficients (see conditions ()and()) in the coposite based on the single-doain PZN-.2PT SC are strongly connected with peculiarities of its elastic and piezoelectric properties as well as with the orientation with respect to the interface x = const (Figure ). The correlation between the piezoelectric coefficients near the absolute inia of the hydrostatic paraeters (Figures 4 and 5) isobservedat different conditions for the piezoelectric coefficients (cf. () and ()), and such behaviour has no analogs aong other piezo-active coposites. In our opinion, the anisotropy of the piezoelectric and elastic properties of the singledoain SC indirectly could influence the volue-fraction dependence of the piezoelectric coefficients shown in Figures 4 and 5. The orientation effect studied in this paper enables us to conclude that the utual arrangeent of the interfaces and the spontaneous polarisation vectors of the SC layers (Figure ) plays an iportant role in foring the significant hydrostatic response of the 2-2 parallel-connected coposite. The single-doain SC layers in the 2-2 coposite studied have advantages over the polydoain layers ainly as the result of the large hydrostatic piezoelectric coefficients fro (8). According to data fro Table 3 and Figure 3,andvalues of the spontaneous polarisation vector P () s of dh 2 pc/n are expected at.9 < <.98 and 7 <β<75,valuesof gh 2 V /N are predicted for.4.7 and 7 <β<75 (ore preferable) or for.3.4 and β = (less preferable because of the lower volue fraction of SC). It is rearkable that these hydrostatic paraeters attain the extree values in the sae narrow range of the orientation angle β. The valueofabsoluteineh = 77.2C/2 is achieved at =.825 and β = 83. Moreover, near this iniu point, conditions () are valid for the piezoelectric coefficients e3j (Figure 4) that bring contributions into eh fro (8). As for the variation of the α angle (inset in Figure ) and the volue fraction d of the 9 doains shown in inset 3 in Figure, it leads to the saller extree values of the effective hydrostatic paraeters fro (8) and(9). In our opinion, such a suppression of the hydrostatic response in coparison with that at the variation of the β angle is directly connected with peculiarities of the elastic and piezoelectric anisotropy of the single-doain PZN-.2PT SC. The hydrostatic piezoelectric perforance and the piezoelectric anisotropy of the studied coposite based on the single-doain PZN-.2PT SC is of value for specialists anufacturing the advanced coposites with pronounced doain effects. The results reported and discussed in the present paper ay stiulate new studies on interrelations between the electroechanical properties of anisotropic coponents and the perforance of the novel piezo-active coposites. Acknowledgents The authors wish to thank professor Dr. A. E. Panich and professor Dr. I.A. Parinov (Rostov-on-Don, Russia), Dr. C. R. Bowen (Bath, UK), and professor Dr. P. Bisegna (Roe, Italy) for their interest in the research probles. The authors are also grateful to Dr. C. R. Bowen (Bath, UK) for his careful reading of the paper of the present publication. This work was partially supported by the adinistration of the Southern Federal University (Project no...9f on basic research), and this support is gratefully acknowledged. References [] A. V. Krivoruchko and V. Yu. Topolov, On the rearkable perforance of novel 2-2-type coposites based on [] poled.93pb(zn /3 Nb 2/3 )O 3 -.7PbTiO 3 single crystals, Physics D, vol. 4, no. 22, pp , 27. [2] V. Yu. Topolov, A. V. Krivoruchko, P. Bisegna, and C. R. Bowen, Orientation effects in 3 coposites based on.93pb(zn /3 Nb 2/3 )O PbTiO 3 single crystals, Ferroelectrics, vol. 376, no., pp. 4 52, 28. [3] V. Yu. Topolov and A. V. Krivoruchko, Orientation effects in 2-2 piezocoposites based on ( x)pb(a /3 Nb 2/3 )O 3 xpbtio 3 single crystals (A = Mg or Zn), Applied Physics, vol. 5, no. 7, Article ID 745, 7 pages, 29. [4] V. Yu. Topolov and A. V. Krivoruchko, Polarization orientation effect and cobination of electroechanical properties in advanced.67pb(mg /3 Nb 2/3 )O 3 -.PbTiO 3 single crystal/polyer coposites with 2-2 connectivity, Sart Materials and Structures, vol. 8, no. 6, Article ID 65, pages, 29. [5] H. Cao, V. H. Schidt, R. Zhang, W. Cao, and H. Luo, Elastic, piezoelectric, and dielectric properties of.58pb(mg /3 Nb 2/3 )O PbTiO 3 single crystal, Applied Physics, vol. 96, no., pp , 24. [6] R. Zhang, B. Jiang, W. Cao, and A. Ain, Coplete set of aterial constants of.93pb(zn /3 Nb 2/3 )O 3 -.7PbTiO 3 doain engineered single crystal, Materials Science Letters, vol. 2, no. 23, pp , 22. [7] R. Zhang, B. Jiang, and W. Cao, Single-doain properties of.67pb(mg /3 Nb 2/3 )O 3 -.PbTiO 3 single crystals under electric field bias, Applied Physics Letters, vol.82,no.5,pp , 23. [8] M. Guennou, H. Daak, and M. P. Thi, 2T doainengineered piezoelectric single crystals: calculations and application to PZN-2%PT poled along [], Applied Physics, vol. 4, no. 7, Article ID 742, 6 pages, 28. [9] R. E. Newnha, D. P. Skinner, and L. E. Cross, Connectivity and piezoelectric-pyroelectric coposites, Materials Research Bulletin, vol. 3, no. 5, pp , 978. [] V. Yu. Topolov and C. R. Bowen, Electroechanical Properties in Coposites Based on Ferroelectrics, Springer, London, UK, 29.

10 Sart Materials Research [] L. V. Gibiansky and S. Torquato, On the use of hoogenization theory to design optial piezocoposites for hydrophone applications, the Mechanics and Physics of Solids, vol. 45, no. 5, pp , 997. [2] V. I. Aleshin, Doain-orientation contribution into constants of the ferroelectric polydoain single crystal and piezoelectric ceraic, Zhurnal Tekhnicheskoi Fiziki, vol. 6, no., pp , 99 (Russian). [3] Y. Xu, Ferroelectric Materials and Their Applications, North- Holland, Asterda, The Netherlands, 99.

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