Polar Symmetry Research Articles

Tailoring of Inverse Energy Flow Profiles with Vector Lissajous Beams

In recent years, structured laser beams for shaping inverse energy flow regions: regions with a direction of energy flow opposite to the propagation direction of a laser beam, have been actively studied. Unfortunately, many structured laser beams generate inverse energy flow regions with dimensions of the order of the wavelength. Moreover, there are significant limitations to the location of these regions. Here, we investigate the possibility of controlling inverse energy flow distributions by using the generalization of well-known cylindrical vector beams with special polarization symmetry—vector Lissajous beams (VLBs)—defined by two polarization orders (p, q). We derive the conditions for the indices (p, q) in order, not only to shape separate isolated regions with a reverse energy flow, but also regions that are infinitely extended along a certain direction in the focal plane. In addition, we show that the maximum intensity curves of the studied VLBs are useful for predicting the properties of focused beams.

Designing Monoclinic Heterophase Coexistence for the Enhanced Piezoelectric Performance in Ternary Lead-Based Relaxor Ferroelectrics.

Enhanced piezoelectric, dielectric properties and thermal stability in ternary relaxor-PbTiO3 based ferroelectric crystals are expected to develop the next-generation of electromechanical devices. However, due to their increased disorder compared to other ferroelectrics, designing a controllable phase boundary structure and engineered domain remains a challenging task. Here, we construct a monoclinic heterophase coexisting in a ternary Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 single crystal with optimized composition and an ultrahigh piezoelectric coefficient of 1400 pC N-1, to quantify the correlation between spontaneous nanopolarity and phase heterogeneity, in an attempt to understand the origin of the exceptional functionalities. By designing an in situ high-resolution spectroscopic-microscopic technique, we have observed Ma and Mc heterophase mixtures spatially separated by the monoclinic heterophase boundary (MHB), which are responsible for the ferroelectric-dominated and relaxor-ferroelectric-dominated nanodomain structure, respectively. Internal energy mapping from optical soft mode dynamics reveals the inhomogeneous polarization and local symmetry on both sides of the MHB. Various molecular polarizabilities and localized octahedral distortions correlate directly with monoclinic regions and electromechanical contribution. This work clarifies the heterogeneity between structure, energy, and polar order and provides a new design freedom for advanced relaxor ferroelectrics.

Morphotropic Relaxor Boundary Construction Highly Boosts the Piezoelectric Properties of Bi-Based Lead-Free Thin Films.

To achieve large electrostrain and low hysteresis, we further optimized a morphotropic phase boundary (MPB) by modulating its local polar symmetries. The construction of a morphotropic relaxor boundary (MRB) in thin films can be achieved by suitable introduction of Bi(Fe0.95Mn0.03Ti0.02)O3 into (Bi0.5Na0.5)TiO3-SrTiO3 to form a solid solution. The designed thin film achieves surprising piezoelectric properties with an inverse piezoelectric coefficient of 179.7 pm V-1 and negligible hysteresis. The composition of two relaxors with different local polar symmetries (tetragonal nanoregions and rhombohedral nanoregions), namely, an MRB, and the coexistence of multiscale domain structures can greatly weaken the anisotropy of polarization, degrade the energy barrier, attenuate the discontinuity of polarization, and achieve a large electrostrain and low hysteresis. The domain dynamics of the PNRs under the action of an external excitation field are analyzed to clarify the enhancement mechanism. This construction of MRBs is feasible for producing lead-free piezoelectric films with high-voltage electrical properties and low hysteresis, and various experimental design and theoretical references are provided.

Three-Dimensional Methylhydrazinium Lead Halide Perovskites: Structural Changes and Effects on Dielectric, Linear, and Nonlinear Optical Properties Entailed by the Halide Tuning

Three-dimensional lead halide perovskites are promising materials for optoelectronic applications. The most famous representative comprise methylammonium (MA+) and formamidinium (FA+) cations, but recently, this group was enlarged by methylhydrazinium (MHy+) analogues that crystallize in polar structures at room-temperature. Properties of three-dimensional (3D) perovskites can be tuned by mixing of molecular cations or halide anions. Here, we report synthesis and physicochemical characterization of mixed-halide MHyPbBrxCl3–x (x = 0.40, 0.58, 0.85, 1.33, 1.95, 2.25, and 2.55) and MHyPbBr2.8I0.2 perovskites. X-ray diffraction data show that all materials feature a polar monoclinic P21 symmetry at room temperature. With the temperature increase, all MHyPbBrxCl3–x perovskites undergo a displacive phase transition to another polar orthorhombic Pb21m phase at T2 ≥ 318 K. The bromine rich crystals (x ≥ 1.33) exhibit an additional order–disorder phase transition to the archetypal cubic Pm3̅m phase at T1 ≥ 409 K. In contrast to MHyPbBrxCl3–x perovskites, MHyPbBr2.8I0.2 undergoes a direct P21 to Pm3̅m phase transition. The temperature at which the cubic phase is stabilized, stability range of the Pb21m phase, and distortion of the lead-halide octahedra decrease with the increase of Br– content. The structural changes affect dielectric, conductivity, and optical properties. In particular, the Br-rich samples show switchable dielectric behavior near 410–420 K. Furthermore, the activation energy of Cl– ionic conductivity increases with the increase of Br– content in phases Pb21m and P21, whereas in phase Pm3̅m, the conductivity of Br– ions increases with the increase of Cl– content. The energy band gap narrows and the photoluminescence (PL) bands exhibit red shift when going from Cl to Br and then to I. Interestingly, whereas PL of the Br-rich and Cl-rich samples is dominated by bound exciton and self-trapped exciton bands, respectively, these bands are suppressed for 2.25 ≥ x ≥ 0.85. The PL color is strongly tuned by doping and changes from greenish-blue for the Cl-rich samples to yellowish-green for MHyPbBr2.8I0.2. SHG studies demonstrate that doping of MHyPbCl3 with Br– ions reduces the difference between SHG signal intensities of the monoclinic and orthorhombic phases, to the extent that beyond x = 1.95, the SHG response of these phases becomes essentially the same. The relative SHG efficiencies of Br–Cl mixed materials at room temperature increase with the increase in Br content.

Polarization singularities and optical chirality in dielectric metasurfaces

We theoretically study the relation between polarization singularities and optical properties in dielectric metasurfaces, or photonic crystal slabs. We focus on nondegenerate photonic bands leading to symmetry-protected Bound States in a Continuum (BICs). First, we discuss how BICs lead to polarization singularities in the far field, whose winding numbers – or topological charges – follows from the symmetry of the lattice. Then, we determine the polarization properties via the Stokes parameters, focusing on the conditions for the occurrence of a nonvanishing circular polarization. Finally, we calculate the optical response in reflection and the degree of circular dichroism. The results shed light on the role of polarization singularities and symmetry in determining the optical chirality.

Unveiling Center‐Type Topological Defects on Rosettes of Lead Zirconate Titanate Associated to Oxygen Vacancies

AbstractUnderstanding the formation of topological defects in ferroelectric materials can provide access to their unusual physics, invaluable for possible applications of domain engineering in nanoelectronics. The present study shows the spontaneous formation of center‐type topological defects in lead zirconate titanate (PZT) films, characterized by a strong in‐plane radial electromechanical response on rosette‐like structures, as revealed by piezoelectric response force microscopy. Multi‐modal electron and X‐ray based techniques provide a comprehensive set of tools for delving at atomic scale the local chemistry, electronic, and crystalline structures. The elemental surface‐sensitivity of soft X‐ray absorption shows chemical segregation and drastic changes in the titanium electronic structure, which have been associated to oxygen vacancies, leading to a mechanism that describe the polarization symmetry on the rosettes. X‐ray nanofluorescence experiments revealed titanium segregation, corroborating with the absorption and low energy electron microscopy images. Taking advantage of a nanobeam, 2D nanodiffraction maps probed the complex microstructure of the domains, revealing its mosaicity and lattice strain at the nanoscale. This study highlights a complex topological structure and provides, by the simultaneous application of a set of analytical tools, a broad comprehension of the formation of center‐type ferroelectric topological defects in PZT.

Electroresistance in multipolar antiferroelectric Cu2Se semiconductor

Electric field-induced changes in the electrical resistance of a material are considered essential and enabling processes for future efficient large-scale computations. However, the underlying physical mechanisms of electroresistance are currently remain largely unknown. Herein, an electrically reversible resistance change has been observed in the thermoelectric α-Cu2Se. The spontaneous electric dipoles formed by Cu+ ions displaced from their positions at the centers of Se-tetrahedrons in the ordered α-Cu2Se phase are examined, and α-Cu2Se phase is identified to be a multipolar antiferroelectric semiconductor. When exposed to the applied voltage, a reversible switching of crystalline domains aligned parallel to the polar axis results in an observed reversible resistance change. The study expands on opportunities for semiconductors with localized polar symmetry as the hardware basis for future computational architectures.

Method for evaluating the polarization performance of cylindrical vector polarized beams

Cylindrical vector polarized (CVP) beams are widely used in many applications due to their special polarized distribution and highly focused properties. It is crucial to evaluate the polarization performance of CVP beams. This paper proposes several polarization parameters for comprehensively evaluating the overall polarization performance and spatial polarization symmetry of CVP beams. To verify this method, several different CVP beams are simulated, and the polarization performance of these beams are indicated. In addition, the trapping models are built to compare trapping capacities of the beams with different polarization performance. The results indicate that the ideal CVP beams demonstrated a higher trapping force than the non-ideal ones, and the trapping force was sensitive to the spatial polarization symmetry of the beams. This evaluation method plays an important role in applications that are susceptible to the polarization performance of the beams.

The crystal structure of LiSc2SbO6

The crystal structures of LiM2SbO6 (M ​= ​Sc, Fe, Mn, In) were originally described as ordered, Pnn2 variants of the Pnna LiSbO3 structure. Recently, however, a single crystal study on the M ​= ​In analogue revealed that its structure is better described as rutile-related with alternating-width chains and Pnnm symmetry. Here, the structure of LiSc2SbO6 (M ​= ​Sc) is similarly revisited with single crystal X-ray diffraction which indicates that it is an Li-ordered variant of the LiIn2SbO6 (M ​= ​In) structure with polar Pmn21 symmetry and a Flack parameter value of 0.5. Solid-state NMR confirms that Li is tetrahedrally coordinated, a key difference between the ordered LiSbO3 and rutile-related models structures. Differential thermal analysis reveals a second-order phase transition between 460 and 480 ​K. With this context, the implications of the low-temperature Flack parameter and powder diffraction data are discussed.

Plasmonic response of a nanorod in the vicinity of a metallic surface: local approach with analytical solution

In this paper we present an analytical solution for the eigenmodes and corresponding electric fields of a composite system made of a nanorod in the vicinity of a plasmonic semi-infinite metallic system. To be specific, we choose Silver as the material for both the nanorod and the semi-infinite metal. The system is composed of two sub-systems with different symmetries: the rod has polar symmetry, while the interface has a rectangular one. Using a boundary integral method, proposed by Eyges, we are able to compute analytically the integrals that sew together the two systems. In the end, the problem is reduced to a one of linear algebra, where all the terms in the system are known analytically. For large distances between the rod and the planar surface, only a few of those integrals are needed and a full analytical solution can be obtained. Our results are important to benchmark other numerical approaches and represent a starting point in the discussion of systems composed of nanorods and two-dimensional materials.

Magnetic-order-induced ferroelectric polarization in the polar antiferromagnets RFeWO6 ( R = Sm, Gd, Er, and Tm)

We report the synthesis, structure, and magnetism-induced multiferroic properties of the polar magnets $R\mathrm{FeW}{\mathrm{O}}_{6}$ (R = Tm, Sm, Gd, and Er). All these compounds crystallize in the orthorhombic structure with the polar symmetry $Pna{2}_{1},$ which results from the ordering of ${\mathrm{Fe}}^{3+}$ and ${\mathrm{W}}^{6+}$ ions at different crystallographic sites. DC magnetization and specific heat measurements confirm the antiferromagnetic order of ${\mathrm{Fe}}^{3+}$ spins at ${T}_{\mathrm{N}1}=14\ensuremath{-}18\phantom{\rule{4pt}{0ex}}\mathrm{K}$ and magnetic ordering of R ions at low temperatures. The magnetic order of ${\mathrm{Fe}}^{3+}$ ions in these compounds is accompanied by a dielectric anomaly and a change in electric polarization. Intriguingly, a second ferroelectric transition occurs at the magnetic ordering temperature (${T}_{\mathrm{N}2}=5.5\phantom{\rule{4pt}{0ex}}\mathrm{K}$) of ${\mathrm{Tm}}^{3+}$ ions in $\mathrm{TmFeW}{\mathrm{O}}_{6}$. The magnetic field dependent behavior of electric polarization varies with R ion, indicating the coupling between $4f\ensuremath{-}3d$ spins. The emergence of change in ferroelectric polarization at the magnetic ordering temperatures demonstrates the multiferroic nature of the polar magnets $R\mathrm{FeW}{\mathrm{O}}_{6}$ (R = Tm, Sm, Gd, and Er). Our study indicates that the aeschynite type family of compounds with polar symmetry can be an excellent platform to understand the role of $4f\ensuremath{-}3d$ coupling on multiferroicity.

Relaxor ferroelectricity driven by ‘A’ and ‘B’ site off-centered displacements in cubic phase with Pmm space group

The present report leads to the development of a lead-free perovskite system (BaCa)(Sn0.11Zr0.05Ti0.84)O3 (BCSZTx); 00.20, exhibiting relaxor ferroelectric behaviour in an average cubic structure. The x-ray diffraction measurements have shown a simple cubic phase with Pmm space group for all the compositions. Despite having a centrosymmetric cubic phase, a slim hysteresis loop has been observed via PE loop measurements. Raman spectroscopic measurements have revealed the presence of local ordering in the macroscopic cubic matrix, corresponding to ‘A’ and ‘B’ sites. The cooperative behaviour of ‘A’ and ‘B’ site off-centered (local) atoms leading to microscopic polar symmetry in the macroscopically cubic matrix is held responsible for the observed relaxor ferroelectric nature. Owing to the aforementioned contrapositive behaviour, these ceramics have exhibited a high value of dielectric constant. Eventually, we have clearly observed a decisive role of Ca2+ dopant at ‘A’ site in BCSZTx ceramic system leading to the enhancement in the relaxor ferroelectric behaviour and dielectric properties. The presence of a slim hysteresis loop along with broad and diffuse dielectric nature makes these ceramics, a potential candidate for energy storage applications.

Symmetry mode analysis of distorted polar/nonpolar structures in A -site ordered SmBaMn2O6 perovskite

We present a comprehensive structural study of the charge-orbital ordering and magnetic phase transitions observed in the $A$-site ordered $\mathrm{SmBa}{\mathrm{Mn}}_{2}{\mathrm{O}}_{6}$ perovskite combining synchrotron radiation x-ray powder diffraction and symmetry-adapted modes analysis. In $\mathrm{SmBa}{\mathrm{Mn}}_{2}{\mathrm{O}}_{6}$, successive phase transitions in charge, spin, and lattice degrees of freedom take place with decreasing temperature at ${T}_{\mathrm{CO}1}\ensuremath{\approx}380\phantom{\rule{0.16em}{0ex}}\mathrm{K}, {T}_{\mathrm{CO}2}\ensuremath{\approx}190\phantom{\rule{0.16em}{0ex}}\mathrm{K}$, and ${T}_{\mathrm{N}}\ensuremath{\approx}250\phantom{\rule{0.16em}{0ex}}\mathrm{K}$. The main difference between the two charge-ordered phases concerns the stacking sequence along the $c$ axis, which is double for the high temperature charge-ordered phase and has led to controversy in the literature. We show that both charge-ordered phases are pseudosymmetric with respect to the ideal undistorted tetragonal structure of $A$-site ordered $R\mathrm{Ba}{\mathrm{Mn}}_{2}{\mathrm{O}}_{6}$ perovskites and lead to two nonequivalent Mn sites. However, the charge segregation stabilizes at about $0.35{e}^{\ensuremath{-}}$ in the low temperature charge-ordered phase, clearly below the nominal separation of one charge unit between ${\mathrm{Mn}}^{3+}$ and ${\mathrm{Mn}}^{4+}$ and undergoes a prominent increase in the high temperature charge-ordered phase when warming above $\ensuremath{\approx}250\phantom{\rule{0.16em}{0ex}}\mathrm{K}$. The two Mn sites are anisotropic in both charge-ordered phases but the analysis of the active modes discloses that only the low temperature charge-ordered phase displays a Jahn-Teller-like distortion for one of the Mn sites. In addition, this low temperature charge-ordered phase has polar symmetry compatible with ferroelectricity along the $a$ axis.

Potential Skyrmion Host Fe(IO3)3: Connecting Stereoactive Lone-Pair Electron Effects to the Dzyaloshinskii-Moriya Interaction

Magnetic skyrmions, which are topologically distinct magnetic spin textures, are gaining increased attention for their unique physical properties and potential applications in spintronic devices. Here we present a design strategy for skyrmion host candidates based on combinations of magnetic spin, asymmetric building units having stereoactive lone-pair electrons, and polar lattice symmetry. To demonstrate the viability of the proposed rational design principles, we successfully synthesized a Fe(IO3)3 polycrystalline sample and single crystals by using a new simplified low-temperature pathway, which is experimentally feasible for extending materials growth of transition metal iodates. Single crystal X-ray and powder synchrotron X-ray diffraction measurements demonstrated that Fe(IO3)3 crystallizes in the polar chiral hexagonal lattice with space group P63. The combined structural features of the macroscopic electric polarization along the c-axis stemming from the coalignment of the stereoactive lone-pairs of the IO3– trigonal pyramid and the magnetic Fe3+ cation residing on the 3-fold rotation axis were selected to promote asymmetric exchange coupling. We find evidence of a predicted skyrmion phase at 14 K ≤ T ≤ 16 K and 2.5 T ≤ μ0H ≤ 3.2 T driven by a Dzyaloshinskii–Moriya (DM) interaction, a conclusion supported by the appreciable DM exchange and the zero-field spiral antiferromagnetic ground state of Fe(IO3)3 deduced from neutron diffraction experiments. The associated magnetic modulation wavelength of the putative skyrmions is expected to be short ∼18 nm, comparable to the period of the DM-driven incommensurate order. This work links stereoactive lone-pair electron effects to enhanced DM interaction, demonstrating a new approach for chemical guidelines in the search for skyrmionic states of matter.

Methylhydrazinium]2PbBr4, a Ferroelectric Hybrid Organic–Inorganic Perovskite with Multiple Nonlinear Optical Outputs

An expansive library of structurally complex two-dimensional (2D) and three-dimensional (3D) lead halide perovskites has emerged over the past decade, finding applications in various aspects of photon management: photovoltaics, photodetection, light emission, and nonlinear optics. Needless to say, the highest degree of structural plasticity enjoys the former group, offering a rich playground for modifications of relevant optoelectronic parameters such as exciton energy. Structural tailorability is reflected in the ease of modification of the chemistry of the organic layers residing between inorganic slabs. In this vein, we show that the introduction of methylhydrazinium cation (MHy+, CH3NH2NH2+) into 2D perovskite gives a material with a record low separation of the inorganic layers (8.91 Å at 300 K). Optical studies showed that MHy2PbBr4 features the most red-shifted excitonic absorption among all known A2PbBr4 compounds as well as a small exciton binding energy of 99.9 meV. MHy2PbBr4 crystallizes in polar Pmn21 symmetry at room emperature (phase III) and at 351 K undergoes a phase transition to modulated Pmnm phase (II) followed by another phase transition at 371 K to Pmnm phase (I). The ferroelectric property of room-temperature phase III is inferred from switching of the pyrocurrent, dielectric measurements, and optical birefringence results. MHy2PbBr4 exhibits multiple nonlinear optical phenomena such as second-harmonic generation, third-harmonic generation, two-photon excited luminescence, and multiphoton excited luminescence. Analysis of MHy2PbBr4 single-crystal luminescence spectra obtained through linear and nonlinear optical excitation pathways indicates that free exciton emission is readily probed by the ultraviolet excitation, whereas crumpled exciton emission is detected under two- and multiphoton excitation conditions. Overall, our results demonstrate that incorporation of MHy+ into the organic layer is an emergent strategy for obtaining a 2D perovskite with polar character and multifunctional properties.

Enhanced piezoelectric response in ferroelectric solid solution with rhombohedral end members

High-performance piezoelectric materials are, in general, ferroelectric solid solutions exhibiting morphotropic phase boundaries (MPB) – a composition driven interferroelectric instabilities. The most common approach to engineer MPB in ferroelectric systems is to choose the end members of the solid solution with different polar symmetries and anticipate for the interferroelectric transformation to occur around a certain critical composition. Here I report a non-classical approach of obtaining MPB by choosing end members of solid solutions with similar polar symmetry (rhombohedral). This is demonstrated in the alloy system x(Na0.5Bi0.5)TiO3–(1-x)Pb(Zr0.6Ti0.4)O3 (NBT-PZT) which shows a narrow MPB region (0.07 ≤ .x ≤ 0.10) at which the piezoelectric response increases remarkably by nearly 3-times to its parent end members. This strategy opens the possibility of discovering new MPB ferroelectric systems with an enhanced electromechanical response.

Experimental generation of helical Mathieu–Gauss vector modes

Vector modes represent the most general state of light in which the spatial and polarisation degrees of freedom are coupled in a non-separable way. Crucially, while polarisation is limited to a bi-dimensional space, the spatial degree of freedom can take any spatial profile. However, most generation and application techniques are mainly limited to spatial modes with polar cylindrical symmetry, such as Laguerre– and Bessel–Gauss modes. In this paper we put forward a novel class of vector modes whose spatial degree of freedom is encoded in the helical Mathieu–Gauss beams of the elliptical cylindrical coordinates. We first introduce these modes theoretically and outline their geometric representation on the higher-order Poincaré sphere. Later on, we demonstrate their experimental generation using a polarisation-insensitive technique comprising the use of a digital micromirror device. Finally, we provide a qualitative and a quantitative characterisation of the same using modern approaches based on quantum mechanics tools. It is worth mentioning that non-polar vector beams are highly desirable in various applications, such as optical trapping and optical communications.

Designed morphotropic relaxor boundary ceramic exhibiting large electrostrain and negligible hysteresis

Electromechanical materials with large electrostrain and low hysteresis are strongly desired for high-precision actuator applications. Despite extensive studies for more than half a century, it is still a challenge to obtain large electrostrain and low hysteresis simultaneously due to the so-called strain-hysteresis trade-off. Here, we report a mechanism to overcome this trade-off: a ceramic composition locating at a morphotropic relaxor boundary (MRB), exhibits enhanced electrostrain and reduced hysteresis as compared with off-MRB compositions. The MRB, a composition-induced boundary separating two relaxors with different local polar symmetries, is attained by transforming an morphotropic phase boundary (MPB) in Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-xPT) through doping lanthanum. The performances of large electrostrain of 0.227% and negligible hysteresis of 3% of MRB composition are the best, as evidenced by occupying a virgin region in the strain-hysteresis chart of relaxor electromechanical ceramics. Moreover, this MRB ceramic maintains the large electrostrain and low hysteresis over a temperature range from 35 to -35 °C. The understanding of abnormal effects of MRB is established through combining microstructure observations and Landau theory analysis: the MRB composition with morphotropic nanodomain structure and higher degree of local structural heterogeneity shows a flatter energy profile with much lower energy barrier, thereby leading to a large electrostrain and negligible hysteresis. Our work demonstrates that the MRB is an effective mechanism to design relaxor materials with large electrostrain and low hysteresis simultaneously. We predict that more high-performance MRB electromechanical materials will be found in properly doped MPB systems.

Realization of structural transformation for the enhancement of magnetic and magneto capacitance effect in BiFeO3\u2013CoFe2O4 ceramics for energy storage application

In this study, (1 − x) BFO-xCFO (CFO, x = 0.00, 0.05, 0.10 and 0.30) ceramics were synthesized by a solid-state reaction method; their compositions were driven by structural, microstructural, vibrational, electrical, magnetic properties; their enhanced magneto capacitance (MC) effect have also been carried out. Reitveld refinement studies of X-ray diffraction data shows composition-driven structural phase transformation from rhombohedral (R3c) to tetragonal (P4mm). Two phonon scattering Raman modes were observed for the higher wavenumber which supports the crystal structural transition in the BFO-CFO. Ferroelectric polarization shows that the polarization increased with increasing CFO concentration, which describes the changes of the polar symmetry of the crystal structure from rhombohedral (R3c) to tetragonal (P4mm). In Further, the maximum efficiency of energy density (η = 68.65%), reversible energy density of 0.138 J/cm3 and the strong magneto capacitance was observed in 0.9BFO-0.1CFO, which belongs to the morphotropic phase boundary (MPB) region near to the BiFeO3-rich region. The magnetic response analysis has shown, the saturation magnetization (Ms) values of 83 emu/gm and 139 emu/gm for pure CFO and 0.7BFO-0.3CFO composite, respectively, and their magnetic behaviours were also confirmed with Arrott–Belov–Kouvel (ABK) plot.

The Graduated Embryo Score of Embryos from Infertile Women with and without Peritoneal Endometriosis.

To determine embryo quality (mean graduated embryo score [GES]) in infertile patients with endometriosis undergoing in vitro fertilization with embryo transfer (IVF-ET) compared with infertile patients without endometriosis. A case-control study was performed comparing 706 embryos (162 patients) divided into 2 groups: 472 embryos derived from patients without endometriosis (n = 109, infertile patients with tubal infertility) and 234 embryos from patients in the study group (n = 53, infertile patients with peritoneal endometriosis). All patients were subjected to IVF using an oestradiol-antagonist-recombinant follicle-stimulating hormone (FSH) protocol for ovarian stimulation. The mean GES was performed to evaluate all embryos at 3 points in time: 16 to 18 hours, 25 to 27 hours, and 64 to 67 hours. Embryo evaluation was performed according to the following parameters: fragmentation, nucleolar alignment, polar body apposition, blastomere number/morphology, and symmetry. The primary outcome measure was the mean GES score. We also compared fertilization, implantation, and pregnancy rates. Although the number of embryos transferred was greater in patients with endometriosis than in the control group (2.38 ± 0.66 versus 2.15 ± 0.54; p = 0.001), the mean GES was similar in both groups (71 ± 19.8 versus 71.9 ± 23.5; p = 0.881). Likewise, the fertilization rate was similar in all groups, being 61% in patients with endometriosis and 59% in the control group (p = 0.511). No significant differences were observed in the implantation (21% versus 22%; [p = 0.989]) and pregnancy rates (26.4% versus 28.4%; p = 0.989). Embryo quality measured by the mean GES was not influenced by peritoneal endometriosis. Likewise, the evaluated reproductive outcomes were similar between infertile patients with and without endometriosis.