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Nephrotic syndrome (NS) represents a heterogenous group of glomerular disorders occurring mainly in children. Accumulated data suggest that patient with NS have an immunological basis. This cross-sectional comparative study was conducted in the Department of Paediatrics, Mymensingh Medical College Hospital (MMCH), Mymensingh during the period of March 2018 to October 2019 to determine the relationship of serum IgE level in frequent relapse and infrequent relapse nephrotic syndrome in children. Thirty cases of frequent relapse and 30 cases of infrequent relapse idiopathic nephrotic syndrome who were admitted in Department of Paediatrics, MMCH were included in this study by purposive sampling technique. After admission written informed consent from parents or guardians obtained. Serum IgE level was measured in all patients of idiopathic nephrotic syndrome during relapse and again four weeks after steroid therapy when patient was in remission. Serum total IgE levels were measured by ADVIA centaur CP immunoassay system. Most of the patient's age was within 2-6 years in both groups. Male children were predominant in both groups. Most of the patients came from rural area. Frequency of relapse per year was significantly higher and 24 hours urine output was significantly lower in frequent relapse nephrotic syndrome than that of infrequent relapse nephrotic syndrome. Significantly higher mean IgE was found in children with frequent relapse nephrotic syndrome (1439.8±388.5 IU/ml during relapse and 852.3±103.7 IU/ml at remission) than infrequent relapse nephrotic syndrome (1109.5±248.3 IU/ml during relapse and 776.6±108.5 IU/ml at remission) at both relapse and remission state. A linear, positive, significant correlation was found between rate of relapse and serum IgE level (Pearson correlation coefficient, r=0.674). Based on results it is concluded that serum IgE is high in relapsing nephrotic syndrome and it is persistently and significantly higher in frequent relapse nephrotic syndrome than infrequent relapse nephrotic syndrome.

There is an increased incidence of rhino orbital mucormycosis during the Coronavirus Disease-2019 (COVID-19) pandemic attributed to diabetes mellitus, corticosteroid usage and immunocompromise caused by COVID-19. In this series, seven biopsy proven cases of mucormycosis (six male patients and one female patient) are presented from a tertiary care center in Eastern India from (May 2021 to June 2021). Empirical systemic liposomal amphotericin B, radical sinus surgery with orbital decompression and irrigation of sinus and orbit with amphotericin B was performed. The mean age of the patients were 42.71±7.34 years with a male preponderance (85.7%). Five patients had orbital involvement (71.42%), and two had cerebral involvement (28.6%). All of them had elevated blood glucose levels, though only three (42.85%) were known cases of type 2 diabetes. The most common manifestations were sinus tenderness (100%), paresthesia (100%), facial swelling (71.42%) and nasal discharge (28.57%). Follow-up at two months showed zero mortality. Timely diagnosis, appropriate management with intravenous amphotericin B and endoscopic radical sinus surgery, debridement of the necrotic tissue proved to be necessary for a good outcome in rhino-orbito-cerebral mucormycosis.

Growth assessment is an essential component of child health surveillance. The most influential tool in the growth assessment is the growth chart. Growth parameters of children are usually interpreted in relation to international standards like the NCHS/1977, CDC/2000 and WHO/2007 growth charts. This comparative study was carried out in the Department of Paediatrics, Mymensingh Medical College, Mymensingh, Bangladesh from November 2014 to October 2015 to compare the growth parameters of children using 2000 CDC standards and 2007 WHO standards. A total of five hundred healthy school children, aged 6 to 10 years were randomly selected proportionately from each class of five government primary schools from Mymensingh city area. Children with physical deformities and acutely ill and those with chronic debilitating diseases were excluded from the study. The mean and median weight, height and BMI were calculated for each age and sex. The median weight, height and BMI were then standardized by converting them to Z-scores (SD) for comparing against known reference values of 2000 CDC and 2007 WHO charts. Among 500 children, 252(50.4%) were boys and 248(49.6%) were girls. The mean age was found 8.0±1.42 years in boys and 8.04±1.42 years in girls. The mean weight was found 24.4±6.36kg in boys and 24.08±6.35kg in girls. The mean height was 125.90±10.16cm in boys and 125.38±10.74cm in girls. The mean weight, height and BMI of boys and girls were found to be lower in all age groups with compared to 2000 CDC standard and 2007 WHO standard but were closer to the WHO standards compared to the CDC standards. According to CDC and WHO in the study it was observed that underweight was found 16.3% and 14.7%, stunting 7.1% and 6.7%, overweight 6.7% and 8.7%, and obese 2.8% and 4.0% respectively in male subjects. On the other hand, in female subjects it was observed that according to CDC chart and WHO chart underweight was found 19.4% and 13.3%, stunting 6.0% and 4.8%, overweight 7.3% and 8.1% and obese 2.0% and 2.0% respectively. The findings in this study imply that growth pattern of Bangladeshi school children is closer with WHO standards and wider from CDC standards.

Acute bronchiolitis is a viral respiratory illness of infants and young children that occurs in the first two years of life. It is a major cause of hospital admissions in Bangladesh. Management of bronchiolitis is a great challenge for the pediatrician both in the outpatient and inpatient department. Because mainstay of treatment options are usually supportive like cool humidified oxygen, fluids, bronchodilators, epinephrine and corticosteroids. A number of agents have been proposed as adjunctive therapies, but their effects are controversial. Nebulized hypertonic saline (3%) has been reported to have some benefit in recent studies. So the objective of this study was to compare the efficacy of nebulized 3% hypertonic saline (HS) with salbutamol and normal saline (0.9%) nebulization in children with acute bronchiolitis. A double-blind randomized controlled trial was conducted in the Department of Paediatrics, Mymensingh Medical College Hospital, Bangladesh from November 2015 to October 2016. A total of 100 children aged one month to two years with acute bronchiolitis admitted in the Pediatric wards of MMCH were included in the study and were randomly assigned to either 3% nebulized hypertonic saline (n=50) or to 0.9% nebulized isotonic saline with salbutamol solution (n=50). The main outcome variables were clinical severity score, length of hospital stay, duration of oxygen therapy and oxygen saturation (SpO2). The therapy was repeated three times on every hospitalization day and the outcome was evaluated two times daily (12 hourly) for 60 hours. Mean duration of oxygen therapy in study group was 33.6±21.7 hours and in control group was 36.8±22.5 hours. But their difference was not statistically significant (p0.05). The mean clinical severity score and mean oxygen saturation of the entire study patients in both groups decreased and increased respectively during hospital stay. There was significant difference of mean clinical severity score and oxygen saturation between admission and follow up-5 in each group (p0.001). But their difference between two groups was not statistically significant (p0.05). Mean duration of hospital stay was 2.91±1.54 days in study group and 3.09±1.85 days in control group. But their difference between two groups was not statistically significant (p0.05). So in acute bronchiolitis nebulized hypertonic saline (3%) is as effective as normal saline (0.9%) and salbutamol nebulization.

The

The R 3TiSb5 ternary compounds, with R a light rare earth (La to Sm) have been reported to crystallize with the anti-Hf5CuSn3-type hexagonal structure (Pearson’s symbol hP18; space-group P63/mcm, N. 193). An early article that reported possible superconductivity in some of these intermetallic phases (namely those with R = La, Ce, and Nd) caught our attention. In this work, we have now refined the crystal structure of the R 3TiSb5 compounds with R = Ce, Pr and Nd by Rietveld methods using high-resolution neutron powder diffraction data. The magnetic ground states of these intermetallics have been investigated by low-temperature magnetization and high-intensity neutron diffraction. We find two different magnetic transitions corresponding to two related magnetic structures at T N1 = 4.8 K (k 1 = [0, 1/2, 1/8]) and T N2 = 3.4 K (k 2 = [0, 0, 1/8]), respectively for Ce3TiSb5. However, the magnetic ordering appears to occur following a peculiar hysteresis: the k 2-type magnetic structure develops only after the k 1-type phase fraction has first slowly ordered with time and the size of the ordered Ce3+ magnetic moment has become large enough to induce the second magnetic transition. At T = 1.5 K the maximum amplitude of the Ce moment in the coexisting phases amounts to μ Ce = 2.15 μ B. For Nd3TiSb5 an antiferromagnetic ordering below T N = 5.2 K into a relatively simpler commensurate magnetic structure with a magnetic moment of μ Nd = 2.14(3) μ B and magnetic propagation vector of k = [0, 0, 0], was determined. No evidence of superconductivity has been found in Nd3TiSb5. Finally, Pr3TiSb5 does not show any ordering down to 1.5 K in neutron diffraction while an antiferromagnetic ground state is detected in magnetization measurements. There is no sign of magnetic contribution from Ti atoms found in any of the studied compounds.

We report thermodynamic and neutron diffraction measurements on a $S=1/2$ metal-organic kagome compound ${{[{\mathrm{Cu}}_{3}({\mathrm{CO}}_{3}){}_{2}{(\mathrm{bpe})}_{3}]\ifmmode\cdot\else\textperiodcentered\fi{}{2\mathrm{ClO}}_{4}}}_{n}$ [bpe=1,2-bis(4-pyridyl)ethane] with a Curie-Weiss temperature of $\ensuremath{\sim}\ensuremath{-}2.9\ifmmode\pm\else\textpm\fi{}0.9\phantom{\rule{0.28em}{0ex}}\mathrm{K}$. The dc and ac magnetization measurements as well as neutron diffraction study show no long-range magnetic order down to 1.5 K. The temperature dependence of specific heat also shows no signature of long-range magnetic order down to 86 mK, as expected for an ideal Heisenberg kagome lattice with a nearest-neighbor antiferromagnetic exchange interaction. The frequency-independent flattening behavior observed in the real part of the ac susceptibility in a zero applied magnetic field below $\ensuremath{\sim}6$ K rules out the presence of a spin glass state and indicates a slowing down of the spin dynamics at low temperatures. Our results suggest that strong quantum fluctuations enhanced by geometrical frustration suppress the long-range magnetic order and a ground state with quasistatic short-range canted antiferromagnetic-type order is realized in the ${{[{\mathrm{Cu}}_{3}({\mathrm{CO}}_{3}){}_{2}{(\mathrm{bpe})}_{3}]\ifmmode\cdot\else\textperiodcentered\fi{}{2\mathrm{ClO}}_{4}}}_{n}$ [bpe=1,2-bis(4-pyridyl)ethane]. The ground state is fragile against external magnetic fields. An applied magnetic field of 125 Oe (and higher) induces ferromagneticlike spin-spin correlations.

We report the anisotropic magnetic properties of the ternary compound ErAl

We have investigated the formation and stability of the binary rare-earth phases, previously reported in the literature as “RPd2”. Although these phases apparently showed a simple stoichiometry, their structure was not that of a Laves phase. After more than half of a century their crystal structure and true stoichiometry have been finally established. The exact stoichiometry of the “RPd2” phases is R10Pd21. The formation of the R10Pd21 compounds has been ascertained for R = Y, Pr, Nd, Sm, Gd to Lu, including Yb; Sc does not form the 10 : 21 phase. Pr10Pd21 forms only as a high temperature phase. These compounds crystallize in the monoclinic Sm10Pd21-type (mS124-C2/m, No. 12, Z = 4); the lattice parameters and unit cell volume decrease linearly on going from Pr to Lu in agreement with the lanthanide contraction. The crystal structure has been determined by X-ray powder diffraction and refined by Rietveld method for the Y, Nd, Tb and Lu compounds. These phases form by a peritectic reaction; the formation temperature, Tf, of some of them has also been measured and compared with the values reported for the “RPd2” phases for which the literature data are available. The increase of both the volume contraction and Tf on going from Pr10Pd21 to Lu10Pd21 suggests an increase of the thermodynamic stability along the series from the lighter to the heavier R. Physical properties (heat capacity, magnetic susceptibility and magnetization, electrical resistivity and magnetoresistance) have been measured for some members of the series (Nd10Pd21, Gd10Pd21, Tb10Pd21, Dy10Pd21, Ho10Pd21, Lu10Pd21 and Y10Pd21). Antiferromagnetic ordering is found for compounds with magnetic R ions at low temperature; the highest Neel temperature, TN, is 10 K for Tb10Pd21. The present experimental work represents a valuable contribution towards a more complete knowledge of the R–Pd systems. In the light of these results, all the binary R–Pd phase diagrams have to be reinvestigated (mainly those based on data assessed by the CALPHAD technique, using optimized thermodynamic parameters) and updated to furnish the material scientists consistent information to challenge the study of more complex systems.

A detailed thermodynamic analysis of the solid and gas phases for the W-C-O-H-S system, used for large area chemical vapor deposition (CVD) of WS2, is presented and compared with experimental results. Given the multivariable nature of the problem, good agreement is observed. CVD phase diagrams which predict parameter windows in which pure WS2 can be synthesized have been provided for important gas phase chemistries. Pure H-2 as a carrier gas is shown to facilitate the largest contamination free process window. The ability to predict completely different outcomes on using Ar versus (Ar+H-2) mixture or pure H-2 as the carrier gas highlights the importance of such thermodynamic modelling. Comparison of these results with a similar system Mo-C-O-H-S has been performed, which indicates some differences in stability windows, but follows similar trends.

Single crystals of the new compound CeCu 0.18 Al 0.24 Si 1.58 have been grown by high-temperature solution growth method using a eutectic Al-Si mixture as flux. This compound is derived from the binary CeSi 2 (tetragonal α-ThSi 2 -type, Pearson symbol tI 12, space group I 4 1 /amd ) obtained by partial substitution of Si by Cu and Al atoms but showing full occupation of the Si crystal site (8 e ). While CeSi 2 is a well-known valence-fluctuating paramagnetic compound, the CeCu 0.18 Al 0.24 Si 1.58 phase orders ferromagnetically at T C =9.3 K. At low temperatures the easy-axis of magnetization is along the a- axis, which re-orients itself along the c -axis above 30 K. The presence of hysteresis in the magnetization curve, negative temperature coefficient of resistivity at high temperatures, reduced jump in the heat capacity and a relatively lower entropy released up to the ordering temperature, and enhanced Sommerfeld coefficient (≈100 mJ/mol K 2 ) show that CeCu 0.18 Al 0.24 Si 1.58 is a Kondo lattice ferromagnetic, moderate heavy fermion compound. Analysis of the high temperature heat capacity data in the paramagnetic region lets us infer that the crystal electric field split doublet levels are located at 178 and 357 K, respectively, and Kondo temperature (8.4 K) is of the order of T C in CeCu 0.18 Al 0.24 Si 1.58 .

We report the anisotropic magnetic properties of the ternary compound ErAl$_2$Ge$_2$. Single crystals of this compound were grown by high temperature solution growth technique,using Al:Ge eutectic composition as flux. From the powder x-ray diffraction we confirmed that ErAl$_2$Ge$_2$ crystallizes in the trigonal CaAl$_2$Si$_2$-type crystal structure. The anisotropic magnetic properties of a single crystal were investigated by measuring the magnetic susceptibility, magnetization, heat capacity and electrical resistivity. A bulk magnetic ordering occurs around 4 K inferred from the magnetic susceptibility and the heat capacity. The magnetization measured along the $ab$-plane increases more rapidly than along the $c$-axis suggesting the basal $ab$-plane as the easy plane of magnetization. The magnetic susceptibility, magnetization and the $4f$-derived part of the heat capacity in the paramagnetic regime analysed based on the point charge model of the crystalline electric field (CEF) indicate a relatively low CEF energy level splitting., 6 pages, 6 figures

A systematic study of the physical properties and microscopic magnetism of Nd

Formation, crystal structure, and macroscopic and microscopic magnetism of the binary $\mathrm{T}{\mathrm{b}}_{3}\mathrm{N}{\mathrm{i}}_{2}$ and derivative pseudobinary $\mathrm{T}{\mathrm{b}}_{3}\mathrm{C}{\mathrm{o}}_{x}\mathrm{N}{\mathrm{i}}_{2\ensuremath{-}x}$ phases have been investigated using an array of experimental methods. While $\mathrm{T}{\mathrm{b}}_{3}\mathrm{N}{\mathrm{i}}_{2}$ crystallizes in the monoclinic $\mathrm{D}{\mathrm{y}}_{3}\mathrm{N}{\mathrm{i}}_{2}$ structure type ($\mathit{mS}20, C2$/m), the substitution of Co for Ni results in a structural transition into the rhombohedral $\mathrm{E}{\mathrm{r}}_{3}\mathrm{N}{\mathrm{i}}_{2}$ type ($\mathit{hR}\mathrm{45}, R\overline{3}h$) at $x(\mathrm{Co})\ensuremath{\approx}0.34$ and beyond in the $\mathrm{T}{\mathrm{b}}_{3}\mathrm{C}{\mathrm{o}}_{x}\mathrm{N}{\mathrm{i}}_{2\ensuremath{-}x}$ system. In both the monoclinic and rhombohedral phases, the addition of Co leads to an anisotropic change of lattice parameters and unexpected reduction of the cell volume. Measurements of bulk properties reveal that these compounds order ferrimagnetically or ferromagnetically at about 100 K. Complex noncollinear ferromagnetic ordering in the Tb sublattices is weakly dependent on composition. For $x$ g 0.34 the long-range magnetic ordering leads to a strong anisotropic magnetostriction accompanied by a symmetry reduction from rhombohedral to triclinic.

${\mathrm{CeMnNi}}_{4}$ exhibits an unusually large spin polarization, but its origin has baffled researchers for more than a decade. We use bulk sensitive hard x-ray photoelectron spectroscopy (HAXPES) and density functional theory based on the Green's function technique to demonstrate the importance of electron-electron correlations of both the Ni $3d$ (${U}_{\text{Ni}}$) and Mn $3d$ (${U}_{\text{Mn}}$) electrons in explaining the valence band of this multiply correlated material. We show that Mn-Ni antisite disorder as well as ${U}_{\text{Ni}}$ play a crucial role in enhancing its spin polarization: Antisite disorder broadens a Ni $3d$ minority-spin peak close to the Fermi level (${E}_{F}$), while an increase in ${U}_{\text{Ni}}$ shifts it toward ${E}_{F}$, both leading to a significant increase of minority-spin states at ${E}_{F}$. Furthermore, the rare occurrence of a valence state transition between the bulk and the surface is demonstrated highlighting the importance of HAXPES in resolving the electronic structure of materials unhindered by surface effects.

We have grown the single crystal of PrRhAl$_4$Si$_2$, which crystallizes in the tetragonal crystal structure. From the low temperature physical property measurements like, magnetic susceptibility, magnetization, heat capacity and electrical resistivity, we found that this compound does not show any magnetic ordering down to 70~mK. Our crystal field calculations on the magnetic susceptibility and specific heat measurements reveal that the 9-fold degenerate $(2J+1)$ levels of Pr atom in PrRhAl$_4$Si$_2$, splits into 7 levels, with a singlet ground state and a well separated excited doublet state at 123~K, with a overall level splitting energy of 320~K., 5 figures

Composition and microstructure of the composite films can be tailored by controlling the CVD process parameters if an appropriate model can be suggested for quantitative prediction of growth. This is possible by applying equilibrium thermodynamics. A modification of such standard modeling procedure was required to account for the deposition of a hybrid film comprised of carbon nanotubes (CNTs), metallic iron (Fe), and magnetite (Fe3O4), a composite useful for energy storage. In contrast with such composite nature of the deposits obtained by inert-ambient CVD using Fe(acac)3 as precursor, equilibrium thermodynamic modeling with standard procedure predicts the deposition of only Fe3C and carbon, without any co-deposition of Fe and Fe3O4. A modification of the procedure comprising chemical reasoning is therefore proposed herein, which predicts simultaneous deposition of FeO1-x, Fe3C, Fe3O4 and C. At high temperatures and in a carbon-rich atmosphere, these convert to Fe3O4, Fe and C, in agreement with experimental CVD. Close quantitative agreement between the modified thermodynamic modeling and experiment validates the reliability of the modified procedure. Understanding of the chemical process through thermodynamic modeling provides potential for control of CVD process parameters to achieve desired hybrid growth. (C) 2016 Elsevier B.V. All rights reserved.

A detailed thermodynamic analysis of the solid and gas phases of the Mo-S-C-O-H system used for large area chemical vapor deposition (CVD) of MoS2 is presented and compared with experimental results. Given the multivariable nature of the problem, excellent agreement is observed. Deviations, observed from thermodynamic predictions, mainly at low temperatures and high flow rates have been highlighted and discussed. CVD phase diagrams which predict parameter windows in which pure MoS2 can be synthesized have been provided for important gas phase chemistries. Pure H2 as a carrier gas is shown to facilitate the largest contamination free process window. CO presence is shown to significantly reduce the nucleation rate and enable large island sizes but at the cost of carbon contamination. Oxygen leaks are shown to result in sulphur contamination. The absence of H2S during cooling is shown to yield Mo due to the reduction of MoS2 by hydrogen. Oxidation of Mo causes oxide contamination.

The temperature dependence of resistivity ρ(T) of a polycrystalline sample and a single crystal sample (current along the [0001] direction) of α - Titanium (Ti) at low temperatures is revisited to understand the electrical charge transport phenomena in this hexagonal closed pack metal. We show that the ρ(T) in single crystal Ti can be explained by considering the scattering of electrons due to electron-phonon, electron-electron, inter-band s-d and electron-impurity interactions, whereas the ρ(T) of polycrystalline Ti could not be explained by these interactions alone. We observed that the effects of the anisotropy of the hexagonal structure on the electronic band structure and the phonon dispersion need to be taken into account to explain ρ(T) of polycrystalline Ti. Two Debye temperatures corresponding to two different directions for the electron-phonon interactions and inter-band s-d scattering are needed to account the observed ρ(T) in polycrystalline Ti.

Polycrystalline samples of $\mathrm{Ce}{({\mathrm{Cu}}_{1\ensuremath{-}x}{\mathrm{Co}}_{x})}_{2}{\mathrm{Ge}}_{2}$ were investigated by means of electrical resistivity $\ensuremath{\rho}(T)$, magnetic susceptibility $\ensuremath{\chi}(T)$, specific heat ${C}_{p}(T)$, and thermoelectric power $S(T)$ measurements. The long-range antiferromagnetic order, which set in at ${T}_{N}=4.1\phantom{\rule{0.28em}{0ex}}\mathrm{K}$ in ${\mathrm{CeCu}}_{2}{\mathrm{Ge}}_{2}$, is suppressed by non-isoelectronic cobalt doping at a critical value of the concentration ${x}_{c}=0.6$, accompanied by non-Fermi-liquid behavior inferred from the power-law dependence of heat capacity and susceptibility, i.e., $C(T)/T$ and $\ensuremath{\chi}(T)\ensuremath{\propto}{T}^{\ensuremath{-}1+\ensuremath{\lambda}}$, down to 0.4 K, along with a clear deviation from ${T}^{2}$ behavior of the electrical resistivity. However, we have not seen any superconducting phase in the quantum critical regime down to 0.4 K.

The trigonal structure of EuMn$_{2}$As$_{2}$ is an anomaly in the tetragonal 122-type pnictide family. We report detailed investigation of the underlying magnetic correlations in single crystal EuMn$_{2}$As$_{2}$ using high resolution elastic neutron scattering measurements. The system undergoes through two successive antiferromagnetic transitions at $T$ = 135 K and 14.4 K, respectively. Numerical modeling of the experimental data reveals the long range antiferromagnetic correlation of Mn-ions in the $a-b$ plane below $T_N1$ = 135 K. Mn spins are aligned closer to the diagonal axis of the unit cell. The lower temperature transition, below $T_N2$ = 14.4 K, is found to arise due to the long range antiferromagnetic correlation of Eu spins that are rotated by $\theta$ = 55 degree from the $c$-axis of the unit cell., Comment: 5 pages, 4 figures

Here, we report an extremely large positive magnetoresistance (XMR) in a single-crystal sample of ${\mathrm{MoSi}}_{2}$, approaching almost ${10}^{7}%$ at 2 K in a 14-T magnetic field without appreciable saturation. Hall resistivity data reveal an uncompensated nature of ${\mathrm{MoSi}}_{2}$ with an electron-hole compensation level sufficient enough to expect strong saturation of magnetoresistance in the high-field regime. Magnetotransport and the complementary de Haas--van Alphen (dHvA) oscillations results, however, suggest that strong Zeeman effect causes a magnetic field-induced modulation of the Fermi pockets and drives the system towards perfect electron-hole compensation condition in the high-field regime. Thus, the nonsaturating XMR of this semimetal arises under the unconventional situation of Zeeman effect-driven electron-hole compensation, whereas its huge magnitude is decided solely by the ultralarge value of the carrier mobility. Intrinsic ultralarge carrier mobility, strong suppression of backward scattering of the charge carriers, and nontrivial Berry phase in dHvA oscillations attest to the topological character of ${\mathrm{MoSi}}_{2}$. Therefore, this semimetal represents another material hosting combination of topological and conventional electronic phases.

We report on the single-crystal growth and anisotropic physical properties of ${\mathrm{CeAgAs}}_{2}$. The compound crystallizes as an ordered variant of the ${\mathrm{HfCuSi}}_{2}$-type crystal structure and adopts the orthorhombic space group $Pmca$ (No. 57) with two symmetry-inequivalent cerium atomic positions in the unit cell. The orthorhombic crystal structure of the single crystal was confirmed from the powder x-ray diffraction and from electron diffraction patterns obtained from the transmission electron microscope. The anisotropic physical properties have been investigated on a good-quality single crystal by measuring the magnetic susceptibility, isothermal magnetization, electrical transport, and heat capacity. The magnetic susceptibility and magnetization measurements revealed that this compound orders antiferromagnetically with two closely spaced magnetic transitions at ${T}_{\mathrm{N}1}=6$ K and ${T}_{\mathrm{N}2}=4.9$ K. Magnetization studies have revealed a large magnetocrystalline anisotropy due to the crystalline electric field with an easy axis of magnetization along the [010] direction. The magnetic susceptibility measured along the [001] direction exhibited a broad hump in the temperature range 50 to 250 K, while typical Curie-Weiss behavior was observed along the other two orthogonal directions. The electrical resistivity and the heat capacity measurements revealed that ${\mathrm{CeAgAs}}_{2}$ is a Kondo-lattice system with a magnetic ground state.

Origin of unprecedentedly high electron mobility observed in the c-axis oriented GaN nanowall networks is investigated by studying the depth distribution of structural, electrical and optical properties of several such high mobility samples grown by molecular beam epitaxy.(MBE) technique for different time durations. It has been found that in two hour grown samples, walls are tapered continuously from the bottom to the top. While in four hour grown samples, walls are flat-topped with the top surface containing certain secondary tip structures. These additional features run along the length of the walls to form a well-connected network. Our study reveals that the carriers are quantum mechanically confined not only in the secondary tip structures but also in the wider part of the walls. The secondary tip structures, which are found to offer higher mobility than the rest of the network, are also identified as the regions of stronger confinement. The effect of mobility enhancement observed in these samples has been attributed to a 2D quantum confinement of electrons in the central vertical plane of the walls. (C) 2015 Elsevier Ltd. All rights reserved.

R11Ni4In9 (R = rare earth) compounds exhibit an unusual self-assembled nano/microfibrous morphology that results in anisotropic structural and magnetic behaviors. The existence of new compounds for R = Dy, Ho, Er, Tm and Lu, has been established (orthorhombic Nd11Pd4In9-type, oC48, Cmmm, Z = 2), showing that the formation of these phases, previously known for R = La–Nd, Sm, Gd, Tb and Y, extends to all of the rare earth elements, except Sc, Eu and Yb. The results of physical property measurements performed on oriented fibers of Tb11Ni4In9, Dy11Ni4In9 and Y11Ni4In9 are presented. Multiple magnetic transitions are observed in Tb11Ni4In9 and Dy11Ni4In9 with the highest ordering temperature, TC, of 112 and 88 K, respectively. Y11Ni4In9 is a Pauli paramagnet down to 2 K. The fibrous microstructure of these compounds leads to a strong anisotropy in their electrical resistivity and magnetization behaviors. The c-axis of the orthorhombic cell is the easy magnetization and high electrical-conductivity direction. Ferrimagnetic-like behavior, with extremely high coercive fields (HC = 6.6 T for Tb11Ni4In9 at 5 K and HC = 5.7 T for Dy11Ni4In9 at 2 K), is found when the fibers (and the c-axis) are oriented parallel to the magnetic field direction; antiferromagnetic-like ground state is observed with the fibers oriented orthogonal (i.e., in the a–b plane). Appearance of a Griffiths phase regime is observed in both compounds before entering the ordered magnetic states. This is more evident for fibers orthogonal to the magnetic field and is even preserved at 1 T. Field induced spin-flop magnetic transitions are also observed in Tb11Ni4In9 and Dy11Ni4In9 with fibers orthogonal and parallel to the field, respectively. First principles calculations have been performed for several representative compounds to explain the underlying phase stability and their magnetism.

The new compound CePt2.4Al0.6 crystallizes in the hexagonal CeNi3-type (hP24, space group P63/mmc, N. 194), with lattice parameters a = 5.5203(3) A and c = 16.886(1) A; its crystal structure represents a nearly ordered ternary derivative of this prototype. The cerium ions in CePt2.4Al0.6 are in the normal trivalent state and order magnetically near 1.6 K as inferred from the low temperature heat capacity. The magnetic ordering is presumably ferromagnetic as suggested by the behavior of heat capacity in applied magnetic fields. The magnetoresistivity below ∼15 K is negative and is tentatively attributed to the presence of ferromagnetic short range order in the paramagnetic state.

Layered transition metal dichalcogenides (TMDs), such as MoS2, are candidate materials for next generation 2-D electronic and optoelectronic devices. The ability to grow uniform, crystalline, atomic layers over large areas is the key to developing such technology. We report a chemical vapor deposition (CVD) technique which yields n-layered MoS2 on a variety of substrates. A generic approach suitable to all TMDs, involving thermodynamic modeling to identify the appropriate CVD process window, and quantitative control of the vapor phase supersaturation, is demonstrated. All reactant sources in our method are outside the growth chamber, a significant improvement over vapor-based methods for atomic layers reported to date. The as-deposited layers are p-type, due to Mo deficiency, with field effect and Hall hole mobilities of up to 2.4 cm(2) V(-1) s(-1) and 44 cm(2) V(-1) s(-1) respectively. These are among the best reported yet for CVD MoS2.

Thermodynamic modeling of the MOCVD process, using the standard free energy minimization algorithm, cannot always explain the deposition of hybrid films that occurs. The present investigation explores a modification of the procedure to account for the observed simultaneous deposition of metallic iron, Fe3O4, and carbon nanotubes from a single precursor. Such composite films have potential application in various device architectures and sensors, and are being studied as electrode material in energy storage devices such as lithium ion batteries and supercapacitors.With ferric acetylacetonate [Fe(acac)3] as the precursor, MOCVD in argon ambient results in a nanocomposite of CNT, Fe, and Fe3O4 (characterized by XRD and Raman spectroscopy) when growth temperature T and total reactor pressure P are in the range from 600°C-800°C and 5-30 torr, respectively. No previous report could be found on the single-step formation of a CNT-metal-metal oxide composite. Equilibrium thermodynamic modeling using available software predicts the deposition of only Fe3C and carbon, without any co-deposition of Fe and Fe3O4, in contrast with experimental observations. To reconcile this contradiction, the modeling of the process was approached by taking the molecular structure of the precursor into account, whereas “standard” thermodynamic simulations are restricted to the total number of atoms of each element in the reactant(s) as the input. When Ocon (statistical average of the oxygen atom(s) taken up by each metal atom during CVD) is restricted to lie between 0 and 1, thermodynamic computations predict simultaneous deposition of FeO1-x, Fe3C, Fe3O4 and C in the inert ambient. At high temperature and in a carbon-rich atmosphere, iron carbide decomposes to iron and carbon. Furthermore, FeO1-x yields Fe and Fe3O4 when cooled below 567°C. Therefore, the resulting film would be composed of Fe3O4, Fe and C, in agreement with experiment. The weight percentage of carbon (∼40%) calculated from thermodynamic analysis matches well with experimental data from TG-DTA.

Specific heat and thermal diffusivity have been studied by means of a high resolution ac photopyroelectric calorimeter in the vicinity of phase transitions in EuFe 2 As 2 : the first one corresponding to the ordering of the Fe 2+ spins concomitant to a structural transition at 188.1 K and the second one to the antiferromagnetic ordering of the Eu 2+ spins at 18.4 K. The weak first order character of the first transition has been confirmed while the critical behavior of the second transition at lower temperature has been established to correspond to the 3D-Ising universality class ( α exp = 0.11 ± 0.03). This is in agreement with the proposed uniaxial arrangement of the Eu 2+ spins lying along the long orthorhombic axis a as reported in literature.

We investigate the electronic structure of a specially prepared highly dense conventional high temperature superconductor, MgB

We present results of our comprehensive studies on single crystalline LaPt

Pseudogap phase in superconductors continues to be an outstanding puzzle that differentiates unconventional superconductors from the conventional ones (BCS-superconductors). Employing high resolution photoemission spectroscopy on a highly dense conventional superconductor, MgB2, we discover an interesting scenario. While the spectral evolution close to the Fermi energy is commensurate to BCS descriptions as expected, the spectra in the wider energy range reveal emergence of a pseudogap much above the superconducting transition temperature indicating apparent departure from the BCS scenario. The energy scale of the pseudogap is comparable to the energy of E2g phonon mode responsible for superconductivity in MgB2 and the pseudogap can be attributed to the effect of electron-phonon coupling on the electronic structure. These results reveal a scenario of the emergence of the superconducting gap within an electron-phonon coupling induced pseudogap., 4 figures

Motivated by the report of superconductivity in R

Modulation of photoluminescence of atomically thin transition metal dichalcogenide two-dimensional materials is critical for their integration in optoelectronic and photonic device applications. By coupling with different plasmonic array geometries, we have shown that the photoluminescence intensity can be enhanced and quenched in comparison with pristine monolayer MoS2. The enhanced exciton emission intensity can be further tuned by varying the angle of polarized incident excitation. Through controlled variation of the structural parameters of the plasmonic array in our experiment, we demonstrate modulation of the photoluminescence intensity from nearly fourfold quenching to approximately threefold enhancement. Our data indicates that the plasmonic resonance couples to optical fields at both, excitation and emission bands, and increases the spontaneous emission rate in a double spacing plasmonic array structure as compared with an equal spacing array structure. Furthermore our experimental results are supported by numerical as well as full electromagnetic wave simulations. This study can facilitate the incorporation of plasmon-enhanced transition metal dichalcogenide structures in photodetector, sensor and light emitter applications.

High-resolution thermal properties have been studied at low temperatures for \(\hbox {R}_{2}\hbox {CoGa}_{8}\) (R = Gd, Tb) by means of an ac photopyroelectric calorimeter in the back configuration, obtaining both thermal diffusivity and specific heat. The antiferromagnetic-to-paramagnetic transition in both materials has been studied in detail in the near vicinity of the Neel temperature. In the case of \(\hbox {Gd}_{2}\hbox {CoGa}_{8}\), the critical parameters for the specific heat have been obtained \((\alpha = -0.126, A^{+}/A^{-}=1.36)\) which indicates that it belongs to the Heisenberg universality class, in agreement with its magnetic structure. In the case of \(\hbox {Tb}_{2}\hbox {CoGa}_{8}\), the shape of the magnetic transition is affected by the presence of two small anomalies which do not allow extraction of the corresponding critical parameters.

A study of the formation of Gd11M4In9 (M = Ni, Pd, Pt) and R11Ni4In9 (R = rare earth) compounds revealed a unique and peculiar property, which is to naturally crystallize in a bundle of self-assembled fibers when cooled from the melt. The fibers, which are nano- to millimeters in cross-section and approximate to 11-40 mm long, grow unidirectionally along a temperature gradient. These compounds adopt the orthorhombic Nd11Pd4In9 structure type (oC48-Cmmm). This structure is layered, with slabs of R atoms alternating with slabs of Ni/In atoms along a short c-axis (much shorter than either the a- or b-axis). The growth direction of the fibers is along the crystallographic c-axis, orthogonal to the a-b plane. Two strong and short In In bonds lie in the a-b plane, which are even shorter than in In metal. Integrated crystal orbital Hamilton population calculations show that the In In bonds create isolated "R8Ni4In9" rods growing along the c-axis, with the In In bonds being part of the rods. This appears to be an important factor explaining the microfibrous nature of these phases. Some physical properties have been measured on the Gd11Ni4In9 homolog. The compound orders ferrimagnetically at T-c approximate to 88 K, and atmore » lower temperatures (46 and 10 K), two other magnetic anomalies were observed, probably due to spin reorientations. As expected from the bonding features, the mechanical, magnetic and electrical properties are strongly anisotropic. (C) 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.« less

Large magnetocaloric effect (MCE) has been observed in R 15 Si 9 C (R = Gd, Tb and Dy) compounds which was studied by magnetization and zero field heat capacity measurements. Gd 15 Si 9 C, Tb 15 Si 9 C and Dy 15 Si 9 C undergo ferromagnetic transition below 170 K, 130 K and 70 K respectively. The Arrott’s plot ( M 2 vs. H / M plot) of the magnetization data and the heat capacity measurement indicate the magnetic transition to be second order in nature. Among Gd, Tb and Dy compounds the maximum value of magnetic entropy change ( Δ S M or MCE) and relative cooling power (RCP) for a magnetic field change of 0–70 kOe are evaluated to be −12.9 J/kg K and 413 J/kg for Dy 15 Si 9 C, around 70 K with no hysteresis loss. The isostructural Gd and Tb compounds also exhibit large values of MCE and RCP around their respectively magnetic transition region. The value of adiabatic temperature change is found to be 5.06 K, 6.64 K and 5.52 K for Gd, Tb and Dy compounds respectively at T C for 0 → 70 kOe of field change. The full-width at half-maximum approaches to 85 K and 64 K respectively for 70 kOe of field change for Tb and Dy counterpart. Large reversible MCE and RCP values indicate that R 15 Si 9 C are promising materials for magnetic refrigeration in appropriate temperature regions.

A systematic study of the physical properties and microscopic magnetism of Nd7Pd3 compound, which in the paramagnetic state crystallizes in the non-centrosymmetric hexagonal Th7Fe3-type structure (hP20-P63 mc; with a = 10.1367(1) A and c = 6.3847(1) A at 300 K), confirms multiple magnetic ordering transitions that occur upon cooling. Antiferromagnetic transition is observed at T N = 37 K, which is followed by ferromagnetic transformation at T C = 33 K. The first-order magnetic transition at T C is magnetoelastic: it involves a change of crystal symmetry from P63 mc to Cmc21 and leads to anisotropic changes of the unit cell parameters. While the antiferromagnetic structure is symmetry allowed in P63 mc, the ferromagnetic structure with magnetic moments along the a-direction of the original hexagonal unit cell induces the first order transition to Cmc21. Density functional theory calculations confirm the experimentally observed ground state with the a-axis as the easy magnetization direction.

We studied the pressure effect up to 8 GPa on antiferromagnet CeAl by means of ac specific heat Cac, ac susceptibility χ′, and electrical resistivity ρ, and constructed temperature–pressure phase d...

We report the growth of a single crystal of PrIr3B2 by Czochralski pulling method and its structural and anisotropic magnetic properties. At room temperature, PrIr3B2 crystallizes in the hexagonal CeCo3B2-type (P6/mmm) structure. However, a change of crystal symmetry is indicated by a hysteretic transition observed in both the resistivity and heat capacity taking place at ≈ 280 K, which is similar to the observed transition from monoclinic (at room temperature) to hexagonal at 395 K previously reported in CeIr3B2 in literature. The jump in the heat capacity at the transition during cooling is nearly 400 J/mol K. The Curie-Weiss behavior of susceptibility conforms to a trivalent state of the Pr ions, which order antiferromagnetically or ferrimagnetically, as inferred from a relatively broad peak in the susceptibility centered around 10 K. The bulk magnetic transition is further corroborated by an anomaly in the heat capacity at low temperatures. Both the temperature dependence of magnetization, and the isothermal magnetization at 2 K reveal a highly anisotropic magnetic behavior in PrIr3B2 with c-axis [0001] as the hard direction of magnetization. The electrical resistivity shows normal metallic behavior down to TN, below which it shows an upturn suggesting the onset of superzone gap.

We study the effect of impurities on the two types of spin-dimers in the hybrid chain-ladder spin 1/2 quantum magnet Sr[Formula: see text]Cu[Formula: see text]O[Formula: see text]. Four different impurities were used, namely, the non-magnetic Zn (0.0025 and 0.01 per Cu) and Al (0.0025 and 0.01 per Cu), and magnetic Ni (0.0025 and 0.01 per Cu) and Co (0.01, 0.03, 0.05 and 0.1 per Cu). These impurities were doped in high-quality single-crystals synthesized by the floating-zone method. The magnetic susceptibility of pristine Sr[Formula: see text]Cu[Formula: see text]O[Formula: see text] is analyzed rigorously to confirm that at low temperatures ([Formula: see text] K), the 'free' spins in the chains undergo a long-distance dimerization as proposed in a recent study (Sahling et al 2015 Nat. Phys. 11 255). The effect of impurity on these dimers is analyzed by measuring the specific heat down to [Formula: see text] K. We found that even at the lower impurity concentration, the long-distance dimers are significantly severed but the quantum entangled spin dimerized state of the chains persists. On the other hand, the other type of spin dimers that form at relatively higher temperatures via an intervening Zhang-Rice singlet are found to be practically unaffected at the lower impurity concentration; but at 1% doping these dimers are considerably severed. The effect of Co impurity turned out to be most unusual displaying a strongly anisotropic response, and with a dimerization gap that suppresses faster along the chain/ladder direction than perpendicular to it as a function of increasing Co concentration.

We discovered a new compound MnCu 4 In with its own hexagonal structure type ( hP 12- P 6 3 mc , ternary ordered derivative of the hexagonal MgZn 2 -type) that becomes ferromagnetic at T C = 540 K. This transition temperature is higher than that found in the MnCu 2 In and MnCu 2 Sn alloys. In contrast, the homologous compound MnCu 4 Sn, which crystallizes in the cubic MgCu 4 Sn-type, orders antiferromagnetically with T N = 110 K. The neutron diffraction studies show ferromagnetic spin orientation in the {1 0 1} plane in MnCu 4 In with a magnetic moment of 4.5 μ B /Mn at 22 K, and a corresponding value of 4.7 μ B /Mn in the antiferromagnetic MnCu 4 Sn with propagation vector K → = 1 2 1 2 1 2 . The first-principles electronic structure calculations show that the unexpected difference in both magnetic and crystal structures of MnCu 4 In and MnCu 4 Sn is due to the difference in the Mn- 3d bands and exchange interactions relating to different crystal anisotropy, coordination numbers, and interatomic distances.

The samples of Gd1-xPrxBa2Cu3O7-δ with compositions x = 0.0, 0.1 & 0.3 were prepared by ceramic route. The XRD study of all samples is carried out. The XRD studies of the samples prepared by ceramic route show GdPr-123 system have an orthorhombic pervoskite structure. The lattice parameters, oxygen content, volume of unit cell, orthorhombic distortion, hole concentration in CuO2 plane and charge on Cu-O plane were evaluated using XRD data. It is found that the lattice parameters, volume of unit cell increase while oxygen content orthorhombic distortion, hole concentration (Psh) and average charge (p) decrease as doping percentage of Pr increases. The resistivity measurement shows the transition temperature decreases while transition width increases with increasing Pr concentration. The suppression of superconductivity may be due to reduction in hole concentration or magnetic pair breaking. We report such qualitative results of Pr substituted Gd-123 in this paper quantitatively.

In this work, we present a detailed study on GaN:Gd layers doped in situ with the Gd concentration ranging from 7×1015 cm-3 3×1017 cm-3 using photoconductivity, photo- thermoelectric power, photoluminescence and vibrating sample magnetometry techniques. Our study shows that Gd incorporation produces large number of defects in the layer, which results in a broad distribution of defect states centered at 450 meV above the valence band. It has been found that multiple types of defects are formed in the layer during the Gd incorporation. However, the density of only one defect type, which results in a strong luminescence feature at 3.05 eV in the photoluminescence spectra recorded at low temperatures in GaN:Gd layers, has been found to decrease significantly upon annealing and at the same time, the saturation magnetization is also observed to reduce, suggesting that these defects are responsible for the magnetic properties observed in this system.