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Rare earth orthoferrites demonstrate great application potentials in spintronics and optical devices due to their multiferroic and magnetooptical properties. In RFeO3, magnetic R3+ undergo a spontaneous spin reorientation in a temperature range determined by R (rare earth), where the magnetic structure changes from Γ2 to Γ4. The b-axis component of their magnetic moment, Mb, is reported in numerous neutron diffraction studies to remain zero at all temperatures. More sensitive magnetometer measurements reveal a small non-zero Mb, which is minute above ∼200 K. Mb increases with cooling and reaches values of ∼10–3 μB/f.u. at temperatures within or below the spin reorientation temperatures. Our results can be explained by assuming the Fe3+ spins as the origin of non-zero Mb, while R3+ spins suppress Mb. The representation analysis of point groups shows that non-zero Mb is associated with a small admixture of the Γ3 phase to Γ2 or Γ4. Such a mixing of the three magnetic phases requires at least a fourth order of the spin Hamiltonian for RFeO3 to describe the non-zero Mb. [ABSTRACT FROM AUTHOR]

Nitrided Y2O3 (YON) interfacial passivation layer (IPL) is used to passivate the HfO2/Ge interface for better interfacial and electrical properties of Ge metal-oxide-semiconductor (MOS) capacitor. Two different approaches were used to prepare the YON IPL, one is to deposit YON directly by sputtering Y2O3 target in Ar+N2 ambient, and the other is to deposit YN first by sputtering Y target in Ar+N2 ambient followed by the annealing in N2+O2 to convert YN to YON. Experimental results indicate that the MOS capacitor fabricated by the latter approach could achieve more excellent interfacial and electrical properties due to more effective suppression of the formation of Ge oxides.

The structural properties of Mn0.92Fe0.08CoGe have been investigated in detail using synchrotron x-ray diffraction in zero and applied pressure (p=0-10 GPa). A ferromagnetic transition occurs around TC=300K and a large magnetic-entropy change -ΔSM=17.3 J/kg K detected at TC for a field change of ΔB-5 T. The field dependence of -ΔSMmax can be expressed as -ΔSMmax β B. At ambient temperature and pressure, Mn0.92Fe0.08CoGe exhibits a co-existence of the orthorhombic TiNiSi-type structure (space group Pnma) and hexagonal Ni2In-type structure (space group P63/ mmc). Application of external pressure drives a structure change from the orthorhombic TiNiSitype structure to the hexagonal Ni2In-type structure. A large anomaly in heat capacity around TC is detected and the Debye temperature θD (=319(±10) K) has been derived from analyses of the low temperature heat capacity, T ≲ 10 K. [ABSTRACT FROM AUTHOR]

The structural and magnetic properties of DyFe11.2Nb0.8 compound have been investigated by high intensity, high resolution synchrotron x-ray diffraction, ac magnetic susceptibility, and dc magnetization measurements as well as Mössbauer spectroscopy (5-300 K). The easy magnetization direction at room temperature is along the c-axis. With decreasing temperature, the magnetocrystalline anisotropy changes from easy-axis to easy-cone at Tsr2 (∼202 K), then to easy plane at Tsr1 (∼94 K). The thermal expansion coefficient obtained from the synchrotron x-ray study exhibits clear anomalies around both of the spin reorientation transition temperatures. The 57Fe hyperfine interaction parameters and magnetic moments values have been determined for the 8i, 8j, and 8f sites from the Mössbauer spectra. [ABSTRACT FROM AUTHOR]

We report structural, caloric, and dielectric properties in the blends of relaxor poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) terpolymer with small amount of poly(vinylidene fluoride-chlorotrifluoroethylene) copolymer, developed on aluminum surface. X-ray diffraction and differential scanning calorimetry results indicate that the copolymer additive disturbs the crystallizing process of the terpolymer. Consequently, relatively high values of the dielectric constant of ≈80, detected in terpolymer films around room temperature, decrease to ≈60 in blends. We show that addition of the copolymer does not influence the relaxor dielectric dynamics of the terpolymer and we explain the detected dielectric response by calculations that take into account the fact that in these heterogeneous systems two similar dynamic processes superimpose in the same temperature range, i.e., relaxor dynamics in the crystalline regions and a glassy transition in the amorphous matrix. [ABSTRACT FROM AUTHOR]

YFeO3 single crystal displays two relaxor-like dielectric relaxations, one at low temperature (170 - 300 K) and one at high temperature (370 - 520 K), which are attributed to the activation of electrons and oxygen vacancies, respectively. Above the temperature at which electrons are activated, the sample displays a large magnetocapacitance effect. Comparison of the impedance Cole-Cole plots measured with and without applied magnetic field reveals that the occurrence of magnetocapacitance effect is accompanied with an increasing in DC conductivity under magnetic field after the activation of electrons, which is explained by the enhancement of electron jumping in Fe2+-O-Fe3+ chains by magnetic field. Thus the magnetocapacitance effect in YFeO3 single crystal can be explained by the combination of the Maxwell-Wagner space charge effect and/or magnetoresistance effect, depending on the frequency range. [ABSTRACT FROM AUTHOR]

A ferroelectric thin film of Aurivillius phase K0.5Bi4.5Ti4O15 (KBT) with a complex bismuth layer-structure was fabricated using the pulsed laser deposition method. The thin film grown on Pt/Ti/SiO2/Si substrate shows a strong c-axis orientation, as revealed by x-ray diffraction results, and platelike growth of grains. A Pt/KBT/Pt capacitor shows a maximum polarization of about 20 μC/cm2. In addition, the capacitor also shows good fatigue resistance, with a decrease of 14.5% in the remanent polarization after 107 switching cycles. This Aurivillius phase with four layers of TiO6 octahedra in its unit cell has a band gap of 3.6 eV, which is greater than that of Bi4Ti3O12. [ABSTRACT FROM AUTHOR]

X-ray diffraction measurements on a 0.65 at. % Nd-doped GdCa[SUB4]O(BO[SUB3])[SUB3] (Nd:GdCOB) crystal revealed a noncentrosymmetric monoclinic space group Cm with lattice parameters a=8.091 ±0.001, b = 16.023±0.002, c = 3.559±0.006 Å, and β = 101.30±0.01°. The fitting primitive cell contained two Nd:GdCOB units. Raman data show that the characteristic spectra of Nd:GdCOB are mainly associated with BO[SUB3] triangles and partly by Ca(1)O[SUB6] octahedra, which implies that the structural rigidity of Nd:GdCOB is mainly associated with the B-O bond stretching and bending modes and partly by the Ca(1)-O bonds. The large distortions of the Gd/NdO[SUB6] and Ca(2)O[SUB6] octahedra intensify the polar forces and anisotropic lattice forces, which indicates excellent nonlinear properties for Nd:GdCOB. Simultaneously, the large distortions of the Gd/NdO[SUB6] octahedra also provide a suitable crystal field for the activated Nd[SUP3+] ions, with the site symmetry m lacking inversion symmetry. This condition increases the probability of the parity-forbidden f →f transitions. Also due to the greater number of anion groups in the primitive cell, this crystal would be expected to be excellent as a self-frequency doubled material. The absorption parameters calculated by Judd-Ofelt theory show that the transitions [SUP4]I[SUB9/2]→[SUP4]F[SUB5/2] and [SUP4]I[SUB9/2]→[SUP2]H[SUB9/2] have larger absorption cross sections and enable the laser-diode pumping band around 808 nm to be more than 30 nm in bandwidth. In the calculated luminescence parameters, the radiation [SUP4]F[SUB3/2]→[SUP4]I[SUB11/2] transition at wavelength of 1060 nm has the largest fluorescence branch-ratio and differential stimulated-emission cross section. [ABSTRACT FROM AUTHOR]

The crystal thermal conduction and thermomechanical properties of (EYGCOB) crystals disclosed by Raman data and thermal expansion of Er: Yb: GdCa(sub 4)O(BO(sub 3))(sub 3) crystals are presented. The suitability of EYGCOB crystal as an infrared radiation laser at 1500nm using a pump wavelength of 1000nm from InGaAs diode laser is described.

OBJECTIVE: This work aimed to analyze the relative expression level of long intergenic non-protein coding ribonucleic acid 1503 (LINC01503) in cholangiocarcinoma tissues and cells, and to explore the effects of LINC01503 on cell proliferation, migration and invasion. PATIENTS AND METHODS: Logarithmic growth phase cholangiocarcinoma cells were selected and transfected with Lipofectamine 2000 (si-LINC01503, si-NC). The expression of LINC01503 was detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). The proliferation of cells was observed by 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetra-zolium bromide (MTT) assay. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay was used to detect cell apoptosis. Transwell assay was used to observe the cell migration and invasion ability. RESULTS: The expression of LINC01503 was significantly increased in cholangiocarcinoma tissues compared with adjacent tissues (p<0.05), and the up-regulated expression of LINC01503 was associated with lymph node metastasis. Compared with normal bile duct cells (HIBEC), cholangiocarcinoma cells (RBE, QBC939) have higher expression of LINC01503, and si-LINC01503 transfection can effectively reduce the proliferation, migration, invasion and epithelial-mesenchymal transition (EMT) of cholangiocarcinoma cells. CONCLUSIONS: LINC01503 is highly expressed in cholangiocarcinoma and can effectively promote the proliferation, migration, invasion and EMT process of cancer cells, and LINC01503 is expected to be a potential biomarker for cholangiocarcinoma. [ABSTRACT FROM AUTHOR]

OBJECTIVE: The aim of this study was to investigate the effects of retinoid X receptor α (RXRα) on the proliferation and apoptosis of pancreatic cancer cells through the transforming growth factor-β (TGF-β)/Smad signaling pathway. PATIENTS AND METHODS: The expression of RXRα in pancreatic cancer tissues and para-carcinoma tissues was detected via immunohistochemistry. Human pancreatic cancer PANC-1 cells were cultured and treated with RXRα in vitro. The apoptosis rate of cells was detected via flow cytometry. Furthermore, changes in the protein expression level of TGF-β/Smad signaling pathway were detected via Western blotting. RESULTS: The protein expression level of RXRα in pancreatic cancer tissues was significantly higher than that of para-carcinoma tissues. RXRα significantly promoted the proliferation and inhibited the apoptosis of pancreatic cancer cells. Moreover, RXRα could also activate the TGF-β/Smad signaling pathway. CONCLUSIONS: RXRα promotes the proliferation and inhibits the apoptosis of pancreatic cancer cells through the TGF-β/Smad signaling pathway. [ABSTRACT FROM AUTHOR]

All TbNi2, TbMn2, and TbNi2Mn compounds exhibit the cubic Laves phase with AB2-type structure in spite of the fact that the ratio of the Tb to transition-metal components in TbNi2Mn is 1:3. Rietveld refinement indicates that in TbNi2Mn the Mn atoms are distributed on both the A (8a) and B (16d) sites. The values of the lattice constants were measured to be a =14.348 Å (space group F-43 m), 7.618 Å, and 7.158 Å (space group Fd-3 m) for TbNi2, TbMn2, and TbNi2Mn, respectively. The magnetic transition temperatures TC were found to be TC=38K and TC=148K for TbNi2 and TbNi2Mn, respectively, while two magnetic phase transitions are detected for TbMn2 at T1=20K and T2=49 K. Clear magnetic history effects in a low magnetic field are observed in TbMn2 and TbNi2Mn. The magnetic entropy changes have been obtained. [ABSTRACT FROM AUTHOR]

Lanthanum doped multiferroic DyFeO3 was synthesized by solid state reaction. X-ray diffraction and refinement show that the lattice parameters of Dy1-xLaxFeO3 increase linearly with the La content. Raman spectroscopy reveals that the short-range force constant in Dy1-xLaxFeO3 is decreased by La3+ ion substitution. The spin reorientation phase transition temperature (TSRPT) is observed to decrease along with the doping level. The antiferromagnetic ordering temperature TN of Fe3+ ions is depressed with increasing doping level. Both decreasing TSRPT and decreasing TN indicate that Fe-Dy and Fe-Fe interactions are weakened by La substitution. It is found that the electron configuration of Fe3+ is high spin state and not affected by the La doping in all the samples above TN. [ABSTRACT FROM AUTHOR]

In this work, we report on our studies on the multiferroic properties of two rare earth chromates, GdCrO3 and YCrO3. Polycrystalline bulks and thin films have been fabricated using conventional solid state reaction and pulsed laser deposition. Magnetic measurements have revealed that both compounds show weak ferromagnetism below the antiferromagnetic Neel temperature, TN, of 170 and 140 K for GdCrO3 and YCrO3, respectively. However the well-developed ferroelectric polarization electrical field loop was not successfully measured for both samples due to their low resistance. The high conductivity of the samples at room temperature is related to the thermal activation of charge carriers at around 200 K in the samples revealed by temperature dependent dielectric measurement. Capacitance measurement at 77 K within magnetic field of 3000 Oe and zero field for GdCrO3 bulk sample shows an increase in 58% in capacitance at 400 kHz by a magnetic field. [ABSTRACT FROM AUTHOR]

Perovskite solid solution ceramics with compositions of 0.9Pb(Fe0.5Nb0.5)O3–0.1PbTiO3, 0.6Pb(Ni1/3Nb2/3)O3–0.4PbTiO3, and 0.6Pb(Co1/3Nb2/3)O3–0.4PbTiO3 were synthesized by the traditional solid state reaction method. Ferroelectric measurements revealed that these samples have well saturated polarization-electrical field loops. Dielectric measurements showed that abnormal dielectric peaks at their Curie temperature were frequency dependent. Both characteristics indicate that these samples are relaxor type ferroelectric materials. Field cooled and zero field cooled magnetization measurements revealed that the 0.6Pb(Ni1/3Nb2/3)O3–0.4PbTiO3 and 0.6Pb(Co1/3Nb2/3)O3–0.4PbTiO3 samples are paramagnetic down to 5 K, while the 0.9Pb(Fe0.5Nb0.5)O3–0.1PbTiO3 sample shows an antiferromagnetic-like ordering starting from around 40 K. Furthermore, a weak ferromagnetism is observed in the 0.9Pb(Fe0.5Nb0.5)O3–0.1PbTiO3 sample, as evidenced by the magnetic hysteresis loop measured at 10 K. The ac susceptibility measurement of this sample showed that the peak position around 40 K is strongly dependent on frequency, indicating a glassy or relaxor type bahavior below that temperature. Therefore, relaxor type ferroelectric and magnetic 0.9Pb(Fe0.5Nb0.5)O3–0.1PbTiO3 is a magnetoelectric relaxor. [ABSTRACT FROM AUTHOR]

Rare earth element doped BiFeO3 thin films were fabricated using the pulsed laser deposition method and various targets made from different starting Fe2O3 and Fe3O4 iron source materials. The films fabricated using the targets made from Fe3O4 exhibit great enhancement in their ferroelectricity, due to greatly reduced electrical leakage, as well as enhanced magnetization compared to those films deposited using targets from Fe2O3. It is suggested that the Fe2+ ion plays an important role in compensating for the charge imbalance and reducing current leakage, as well as enhancing the magnetic moment through the introduction of antiferrimagnetic ordering at Fe2+ site. [ABSTRACT FROM AUTHOR]

Rare earth element doped BiFeO3 thin films were fabricated using the pulsed laser deposition method and various targets made from different starting Fe2O3 and Fe3O4 iron source materials. The films fabricated using the targets made from Fe3O4 exhibit great enhancement in their ferroelectricity, due to greatly reduced electrical leakage, as well as enhanced magnetization compared to those films deposited using targets from Fe2O3. It is suggested that the Fe2+ ion plays an important role in compensating for the charge imbalance and reducing current leakage, as well as enhancing the magnetic moment through the introduction of antiferrimagnetic ordering at Fe2+ site. [ABSTRACT FROM AUTHOR]

Bi1-xLaxFeO3 ceramics with x=0, 0.1, 0.2, and 0.3 have been synthesized by solid state reaction, starting from metal oxides. A series of structure transformations is found to depend upon the doping level. Below 10% La doping, Bi1-xLaxFeO3 maintains the rhombohedral structure of BiFeO3. However, for Bi0.8La0.2FeO3 and Bi0.7La0.3FeO3, the structures change to the orthorhombic and tetragonal, respectively. La doping significantly reduces electric leakage and leads to successful observation of electrical polarization hysteresis loops. Doping with La also enhances the ferromagnetic moment, due to the broken cycloid spin structure caused by the changes in the crystalline structure. [ABSTRACT FROM AUTHOR]

We report for the first time the Al and C codoping effect on the structures and superconductivity in MgB2. It was found that both the lattice parameters and the Tc decreased monotonically with increasing doping level of both Al and C. The Tc dropped to 27.5 and 7 K for x=0.2 and for x=0.4, respectively. The reduction of Tc for the codoping was found to be quicker than for individual Al doping and slower than for individual C doping at the same doping levels. First-principles calculations indicated that the observed decrease in Tc for the codoped MgB2 can be understood in terms of a band filling effect due to the electron doping by both Al and C. However, it is suggested that other factors may also play a role in the Tc reduction in the real Mg1-xAlxB2-xCx samples. Furthermore, the Al and C codoping also reduces Jc and weakens flux pinning in MgB2. [ABSTRACT FROM AUTHOR]

In this work, we report on our studies on the band structure calculations, structures, transport, and magnetic properties in two dimensional layer structured perovskite compounds Sr2-xLaxCoO4. Structure refinement results reveal that these compounds crystallized in K2NiF4-type structures with space group I4/mmm. The temperature dependence of resistivity shows a semiconductorlike behavior over a wide range of temperatures, a metal-insulator transition at 240 K, and an upturn at 160 K for the x=1, 1.25, and 0.75 samples. A coercive field is about 1 T for the sample with x=0.75, while it is about 0.05 T for x=0.75 and 0.1 T for the x=1.25 samples. A negative field hysteresis magnetoresistance in close correlation with the coercive field has been observed and can be explained by the grain boundary tunneling effect. The first-principles band structure calculations were carried out for Sr1.5La0.5CoO4 and the results indicate that the system is metallic with a high spin polarization which is responsible for the observed large magnetoresistance. [ABSTRACT FROM AUTHOR]

Plane-wave pseudo-potential methods based on density functional theory are used to study the electronic structures, magnetic, and half-metallic properties of the equiatomic quaternary Heusler alloys NbVMnAl and NbFeCrAl. Calculated results reveal that NbVMnAl and NbFeCrAl alloys are newly designed half-metallic ferrimagnets with a total magnetic moment ( M ) of 2 μ . We found that the Slater-Pauling rule, i.e., the relationship between the M and the total number of valence electrons ( Z ) of these two alloys was different. For NbVMnAl alloy, it obeys the M = | Z − 18| rule. For NbFeCrAl, it satisfies the M = | Z − 24| rule. Also, we observed that the half-metallic band gap (HM-BG) of these two alloys was different. Namely, for one material (NbFeCrAl), it is located in the spin-up channel, and in the other (NbVMnAl), it is located in the spin-down channel. To explain these phenomena, in this work, the generalized electron-filling rule was investigated, and the origin of the HM-BG of NbVMnAl and NbFeCrAl was studied. We hope that our work may provide theoretical guidance in searching for Nb-based equiatomic quaternary Heusler half-metals in the future. [ABSTRACT FROM AUTHOR]

OBJECTIVE: Previous research indicated that miR-144-3p was associated with the regulation of the carcinogenic processes, but the role of miR-144-3p in glioblastoma (GBM) remains unclear. In this study, we aimed to analyze the role of miR-144-3p in GBM. PATIENTS AND METHODS: The expression of miR-144-3p was measured in GBM tissues and adjacent non-malignant tissues using qRT-PCR. The correlation of miR-144-3p with clinicopathological features and prognosis was also analyzed. Cell proliferation, invasions, and migration assay were applied to assess the function of miR-144- 3p in vitro. Bioinformatics prediction and luciferase assays were employed to identify the predicted microRNA (miRNA) which regulates Frizzled-7 (FZD7). The levels of FZD7 and FZD7 mRNA were determined by Western blot and RT-PCR. RESULTS: The results showed that the miR-144-3p expression was significantly downregulated in tumor tissues and GBM cell lines compared with that in normal brain tissues and the normal human astrocytes. The levels of miR-144-3p were negatively correlated with the status of WHO grade and recurrence. Furthermore, patients with low serum levels of miR-144-3p had a significantly shorter median overall survival rate. Multivariate Cox regression analysis confirmed that low level of miR-144-3p expression predicted poor prognosis independently. Further function assays showed that miR-144-3p inhibited proliferation invasion and migration of GBM cells. Finally, miR-144-3p was demonstrated to bind to the wild-type 3' untranslated region of FZD7 but not with its mutant. CONCLUSIONS: The results of the present study indicate that miR-144-3p suppresses tumor metastasis by targeting FZD7. This work also provides strong evidence that miR-144-3p is an independent prognostic factor for patients with GBM. [ABSTRACT FROM AUTHOR]

Bi2-xPbxSr2Ca1-yGdyCu2O8+δ (x=0.34 and y=0.18, 0.34) crystals were grown by the self-flux method. The crystals have a cleavage thickness of only half unit cell up to two unit cells with Tc only dropping 20 K as y is increased from 0.18 to 0.34 for as-grown crystals. However, Tc increased to almost the same value of about 80 K after annealing in air regardless of the Gd doping levels. The co-doping produced enhanced flux pinning compared to the sole Gd doping. A secondary peak effect presented in crystals with x=0.34 and y=0.34 was explained by phase segregations containing Gd-rich clusters. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]