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Access and use of this website and the material on it are subject to the Terms and Conditions set forth at Ground state of the relaxor ferroelectric Pb(Zn1/3Nb2/3)O3 Xu, Guangyong; zhang, Z.; Bing, Y.; Ye, Z.-G.; Stock, C.; Shirane, G.http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/jsp/nparc_cp.jsp?lang=fr L'accès à ce site Web et l'utilisation de son contenu sont assujettis aux conditions présentées dans le site LISEZ CES CONDITIONS ATTENTIVEMENT AVANT D'UTILISER CE SITE WEB. NRC Publications Record / Notice d'Archives des publications de CNRC:http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?lang=en http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?lang=fr READ THESE TERMS AND CONDITIONS CAREFULLY BEFORE USING THIS WEBSITE.http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/jsp/nparc_cp.jsp?lang=en Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n'arrivez pas à les repérer, communiquez avec nous à PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. Questions? Contact the NRC Publications Archive team atPublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. If you wish to email the authors directly, please see the first page of the publication for their contact information. NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur. For the publisher's version, please access the DOI link below./ Pour consulter la version de l'éditeur, utilisez le lien DOI ci-dessous.http://doi.org/10.1103/PhysRevB.67.104102Physical Review B, 67,10 High energy x-ray diffraction measurements on Pb(Zn 1/3 Nb 2/3 )O 3 ͑PZN͒ single crystals show that the system does not have a rhombohedral symmetry at room temperature as previously believed. The phase ͑X͒ in the bulk of the crystal gives Bragg peaks similar to that of a nearly cubic lattice with a slight tetragonal distortion. The Bragg profile remains sharp with no evidence of size broadening due to the polar microcrystals. However, in our preliminary studies of the skin, we have found the expected rhombohedral ͑R͒ phase as a surface state. On the other hand, studies on an electric-field poled PZN single crystal clearly indicate a rhombohedral phase at room temperature.

X-ray diffraction studies on a Pb(Zn 1/3 Nb 2/3 )O3 (PZN) single crystal sample show the presence of two different structures. An outer-layer exists in the outer most ∼ 10 to 50 µm of the crystal, and undergoes a structural phase transition at the Curie temperature TC ≈ 410 K. The inside phase is however, very different. The lattice inside the crystal maintains a cubic unit cell, while ferroelectric polarization develops below TC. The lattice parameter of the cubic unit cell remains virtually a constant, i.e., much less variations compared to that of a typical relaxor ferroelectric, in a wide temperature range of 15 K to 750 K. On the other hand, broadening of Bragg peaks and change of Bragg profile line-shapes in both longitudinal and transverse directions at TC clearly indicate a structural phase transition occurring.

The structure and the dielectric properties of Pb(Zn 1/3 Nb 2/3 )O 3 (PZN) crystal have been investigated by means of high-resolution synchrotron xray diffraction (with an x-ray energy of 32 keV) and dielectric spectroscopy (in the frequency range 100 Hz-1 MHz). At high temperatures, the PZN crystal exhibits a cubic symmetry and polar nanoregions inherent to relaxor ferroelectrics are present, as evidenced by the single (222) Bragg peak and by the noticeable tails at the base of the peak. At low temperatures, in addition to the well-known rhombohedral phase, another low-symmetry, probably monoclinic, phase is found. The two phases coexist in the form of mesoscopic domains. The ferroelectric phase transition is diffuse and observed between 325 and 390 K, where the concentration of the low-temperature phases gradually increases and the cubic phase disappears upon cooling. However, no dielectric anomalies can be detected in the temperature range of the diffuse phase transition. The temperature dependence of the dielectric constant shows a maximum at higher temperature (T m = 417-429 K, depending on frequency) with the typical relaxor dispersion at T < T m and the frequency dependence of T m fitted to the Vogel-Fulcher relation. Application of an electric field upon cooling from the cubic phase or poling the crystal in the ferroelectric phase gives rise to a sharp anomaly of the dielectric constant at T ≈ 390 K and greatly diminishes the dispersion at lower temperatures, but the dielectric relaxation process around T m remains qualitatively unchanged. The results are discussed in the framework of the present models of relaxors and in comparison with the prototypical relaxor ferroelectric Pb(Mg 1/3 Nb 2/3 )O 3 .

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