Diamagnetic Susceptibility Measurements Research Articles

Precise measurements of diamagnetic susceptibility of benzophenone and paraffin by using a magnetic levitation technique

Measurements for temperature dependence of diamagnetic susceptibility were performed under the magnetic levitation condition. The magnetic susceptibility of a single crystal of benzophenone showed monotonous decrease toward to the melting point with increasing temperature. The minimum change of the susceptibility was detected by 1.4 × 10−12 m3/kg. On the contrary, slight increase was observed below the melting point in the case of paraffin. The susceptibility of a paraffin melt was found to be smaller than that of the solid state. It was demonstrated that the magnetic levitation enables sensitive and contactless measurements of the diamagnetic susceptibility across the melting point.

Pressure effect on superconducting properties of LaO1-xFxFeAs (x=0.11) superconductor

Diamagnetic susceptibility measurements under high hydrostatic pressure (up to 1.03 GPa) were carried out on a newly discovered Fe-based superconductor LaO1-xFxFeAs (x=0.11). The transition temperature TC, defined as a point at the maximum slope of superconducting transition, was enhanced almost linearly by hydrostatic pressure, yielding a dTC/dP of about 1.2 K GPa−1. Differential diamagnetic susceptibility curves indicate that the underlying superconducting state is complicated. It is suggested that pressure plays an important role on pushing the low TC superconducting phase toward the main (optimal) superconducting phase.

Magnetochemistry of Boron Hydride Structures. Empirical Aspects

AbstractFor Abstract see ChemInform Abstract in Full Text.

Magnetic Levitation of Plastic Chips: Applications for Magnetic Susceptibility Measurement and Magnetic Separation

Magnetic levitation of polyethylene, polycarbonate, polypropylene, polystyrene, poly(methyl methacrylate) and polyamide was carried out using a compact superconducting magnet (vertical bore, 1500 T2 m-1). First, their diamagnetic susceptibilities were calculated from the product of the magnetic field and the field gradient necessary for levitation. Second, polypropylene, polyamide, and poly(ethylene terephthalate) chips were separated by magnetic levitation. Magnetic levitation is shown to be a convenient and useful technique for both diamagnetic susceptibility measurements and magnetic separations of diamagnetic substances.

Magnetochemistry of boron hydride structures. Empirical aspects

The reviews and monographs on magnetochemistry of boron compounds are discussed. The structural peculiarities of borane derivatives relevant to magnetochemical calculations of diamagnetic contributions are are considered. Experimental measurements of diamagnetic susceptibility for deltahedral B10H 10 2− and B12H 12 2− cluster closo-anions were used to derive the diamagnetic atomic increments of the B atoms (χB) with coordination numbers 5 and 6. The atomic increments χB thus obtained were used to calculate molecular diamagnetic susceptibility χM of borane derivatives. Diamagnetic susceptibility χM was measured and calculated for the series of borane derivatives BnH n 2− and B10H12L2 (L is a Lewis base)and cobalt(III) derivatives of ortho-carborane(12) [(B9C2H11)2Con(B8C2H10) n−1] n−. Diamagnetic increments were obtained for |B10H12| fragments and (B9C2H11)2− and (B8C2H10)4− ligands. The increments can be employed for calculating χM for novel compounds. The calculated values of χM coincide with the experimental values within 2%–6%.

Structure-Diamagnetic Susceptibility Correlations in Regular Alternating Terpolymers of Ethene and Propene with Carbon Monoxide

A series of regular alternating terpolymers of ethene and propene with carbon monoxide with different Et/CO content was characterized by wide- and small-angle x-ray scattering, differential scanning calorimetry, and diamagnetic susceptibility measurements. All terpolymers proved to be amorphous at room temperature. The occurrence of multiple endothermic effects appearing at T m , above the glass transition temperature T g , and extending over a fairly broad temperature range is discussed on the basis of a three-dimensional network of Et/CO nanocrystals spanning the continuous, noncrystalline Pr/CO matrix in the initial samples. Magnetic susceptibility data obtained over the temperature range studied confirm our previous findings: accordingly, it is the onset of large-scale (segmental) mobility, rather than density variations, that is responsible for the discontinuous changes of diamagnetic susceptibility observed, at T g and T m . The unusual large differences found between absolute χ-values for samples with different chain composition are interpreted in light of the classical theory of random copolymerization, assuming that terpolymer chains are made up of two randomly distributed “virtual comonomers,” (Et/CO) and (Pr/CO).

Two-dimensional fluctuations in the magnetization of the high-temperature superconductor LaBaCaCu 3O 7− δ

We report measurements of magnetization and diamagnetic susceptibility in polycrystalline LaBaCaCu3O 7− δ in high magnetic fields (20–50 kOe). The sample has a zero-field transition temperature T c0 =77 K and a transition width of 2.0 K. The results show large fluctuation effects, which can be explained by Ginzburg–Landau fluctuation theory for a two-dimensional system. Using a theoretical model based on the lowest Landau-levels approximation, the magnetization data are fitted with good agreement. The weak-field fluctuation diamagnetic susceptibility above T c can be fitted well in terms of the 2D Lawrence–Doniach model.

Transition to a quasi-insulating state in quasi-crystalline AlPdRe

We present results about electronic properties of quasi-crystalline AlPdRe samples, assumed to be on each side of the metal–insulator transition. The structural quality and the chemical composition are investigated by X-ray diffraction, scanning electron microscopy and microprobe analysis. Conductivity is reported. The density of states (DOS) at the Fermi level is probed by specific heat and diamagnetic susceptibility measurements, and the energy dependence around the Fermi level by scanning tunneling spectroscopy. The DOS at the Fermi level and the preopening of a correlation gap confirm the proximity to the metal–insulator transition, as indicated by the conductivity. The transition towards an insulating state could be related to local compositional fluctuations.

Formation of high-T c phases of the system Bi-Pb-Sr-Ca-Cu-O in a fluxed KCl melt

The influence of the conditions of synthesis and annealing on the ratio of the volumes and the temperature Tcn at which transition to the superconducting state begins is investigated on the basis of diamagnetic susceptibility measurements and x-ray phase analysis for bismuth 2212 and 2223 phases obtained from solution in a KCl melt. It is found that the value of Tcn for the 2212 phase decreases as the temperature and the holding time are increased in synthesis. The 2212–2223 transition in the fluxed KCl melt takes place in the presence of an oxygen deficiency, and the width of the transition interval to the superconducting state of the 2223 phase depends on the cooling rate of the fluxed melt after isothermal holding and also on subsequent annealing in air. Temperatures Tcn=107 K, 90 K, and 20 K are observed for unannealed crystals of the 2223 phase with average dimensions 50×50 µm. Air annealing leads to oxygen saturation of their lattice, and Tcn=107 K throughout the entire structure of the crystal.

Structure and superconductivity of C 60 fullerides

In alkali-metal (A) doped C 60 fullerides superconductivity is found only for face-centered cubic (f.c.c.) crystal phases with the composition A 3C 60. The highest T c of 33 K found in these f.c.c. A 3C 60 superconductors family is surpassed only by that of the high T c, copper oxides. We describe here the stability and dopant site selectivity of A 3C 60 fullerides as well as the factors controlling the f.c.c. lattice parameters. Superconductivity studied by diamagnetic susceptibility measurements is described in detail, especially in the small lattice parameter region. The relationship between the f.c.c. structure and the superconductivity is described and the phonon frequency associated with electron pairing is discussed within the framework of the phonon-mediated type McMillan equation. Experimental results, which are not well understood, are also discussed with reference to the literature.

Size evaluation of graphitic crystallites in activated carbon fibers from diamagnetic susceptibility measurements

Diamagnetic susceptibilities of various kinds of activated carbon fibers (ACFs), nonporous carbon black, and Grafoil were measured under an N 2 atmosphere in the temperature range of 273 to 423 K. An empirical relationship between the diamagnetic susceptibility and molecular structure was derived from the literature for polynuclear aromatic compounds without hydrogen atoms. The unit size of graphitic crystallites in ACFs was evaluated from the derived relationship.

Orientational order in aramid solutions determined by diamagnetic susceptibility and birefringence measurements

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOrientational order in aramid solutions determined by diamagnetic susceptibility and birefringence measurementsStephen J. PickenCite this: Macromolecules 1990, 23, 2, 464–470Publication Date (Print):January 1, 1990Publication History Published online1 May 2002Published inissue 1 January 1990https://doi.org/10.1021/ma00204a019RIGHTS & PERMISSIONSArticle Views148Altmetric-Citations24LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (782 KB) Get e-Alerts Get e-Alerts

Glass behavior and the H-T phase diagram of the high-Tc ceramic superconductors YBa2Cu3O7, EuBa2Cu3O7, and GdBa2Cu3O7.

We report systematic field-cooled (FC) and zero-field-cooled (ZFC) diamagnetic susceptibility measurements in polycrystalline samples of the high-${T}_{c}$ oxide superconductors R${\mathrm{Ba}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{7}$, where R=Y, Eu, or Gd. We focus mainly on the temperature range near ${T}_{c}$, where the FC and ZFC curves split up below a characteristic temperature, similar to the behavior of spin glasses. This temperature depends on the applied magnetic field and defines a crossover line in the H-T plane separating ergodic and nonergodic behavior, in close resemblance to what is found in conventional spin glasses. We suggest that this is a general characteristic of the ceramic oxide superconductors. Moreover, our data allow us to obtain a more detailed high-temperature H-T phase diagram, where a lower temperature bound for the superconducting glasslike state is proposed.

The dependence of microstructure and superconducting phase formation on post-sintering cool-rate of BiCaSrCu2Ox ceramic

Ceramic samples of nominal composition BiCaSrCu2Ox have been fabricated via mixed-oxide and spray-dried routes. The former method has consistently yielded samples of higher mechanical density (5.20 cf 4.04 g cm-3). In an attempt to optimise the formation of the higher-temperature superconducting phase (Tc approximately 105 K), samples produced by both methods have been subjected to a range of post-sintering cool-rates. AC diamagnetic susceptibility measurements to 4.2 K indicate that this process parameter determines critically the superconducting properties of resultant samples. In particular, slow cool-rates, or equivalently long sintering times, are essential if complete volume superconductivity is to be achieved. Microstructural analysis reveals that a 'flaky' powder morphology yields samples of good mechanical strength. Evidence of the higher-Tc phase has only been detected in low density samples, suggesting that the oxygen content of the lattice plays a significant role in the formation of this phase. A distinct acicular morphology for the higher-Tc phase has been observed compared with a flaky grain geometry characteristic of the 85 K phase. The acicular microstructure is significantly less sensitive to the application of magnetic fields than the latter. It is suggested that the difficulties experienced in producing single phase material which exhibits superconductivity above 100 K in this system could be attributed to a variation in stoichiometry within a single-crystal lattice.

Physical processing effects on polycrystalline YBa2Cu3Ox

The effect of heating YBa2Cu3Ox in vacuum to 600 °C has been studied using photoelectron spectroscopy and diamagnetic susceptibility measurements. Evidence of two chemically distinct copper and barium species is found in single phase samples at room temperature cleaned by gentle heating at 450 °C. Such annealing also increases the volume diamagnetic susceptibility of the samples which suggests that the preferred stoichiometry of growth does not lead to an optimum superconducting phase. Samples cleaned by vacuum scraping or ion bombardment reveal more amorphous XPS structure and are less indicative of bulk properties.

Aluminum substitution in Ba2YCu3O7.

We have investigated the effect of aluminum incorporation on the structure and superconducting transition temperature of single crystals of high-${T}_{c}$ cuprate perovskite superconductors. The use of alumina crucibles for crystal growth results in incorporation of aluminum to varying extents in crystals of composition ${\mathrm{Ba}}_{2}\mathrm{Y}{\mathrm{Cu}}_{3\ensuremath{-}x}{\mathrm{Al}}_{x}{\mathrm{O}}_{7}$, $x=0\ensuremath{-}0.22$. We have performed x-ray studies on several crystals to determine structural effects of Al incorporation. We find that aluminum substitutes only for copper atoms in the chains. Superconducting transition temperatures ${T}_{c}$ determined by dc diamagnetic susceptibility measurements change only slightly, to \ensuremath{\sim}80 K for $x=0.1$, then drop sharply with higher aluminum concentrations. Results are discussed in relation to the importance of the Cu-O chains and oxygen stoichiometry to superconductivity in ${\mathrm{Ba}}_{2}$Y${\mathrm{Cu}}_{3}$${\mathrm{O}}_{7}$.

ChemInform Abstract: Subsolidus Compatibilities in the Y2O3‐BaO‐CuO System via Diamagnetic Susceptibility.

AbstractSubsolidus compatibilities in the title system (involving the 90 K superconducting 1:2:3 compound) have been determined by optical microscopy, X‐ray diffraction, and diamagnetic susceptibility measurements.

Subsolidus Compatibilities in the Y2O3‐BaO‐CuO System via Diamagnetic Susceptibility

Subsolidus compatibilities in the YO1.5‐BaO‐CuO system involving the superconducting 1:2:3 compound have been determined via optical microscopy, X‐ray diffraction, and diamagnetic susceptibility measurements. The susceptibility is particularly sensitive to the presence or absence of the superconducting phase.

Aluminum Incorporation in Cuprate Perovskites

ABSTRACTAluminum incorporation in cuprate perovskite single crystals has been studied by single crystal x-ray diffraction. We find that Al substitutes for copper in the Cu-O chains only. Superconducting transition temperatures, Tc, determined by dc diamagnetic susceptibility measurements, change only slightly, to «80K for ×=0.l, then drop sharply with higher aluminum concentrations.

Correlation of IR spectroscopic, heat capacity, diamagnetic susceptibility and enzymatic measurements on lysozyme powder.

The interaction between protein and water is of fundamental importance for processes ranging from protein folding and enzymatic activity to anhydrobiosis. In this letter we bring together results from diverse types of measurements to give a unified picture of the hydration process for lysozyme. The data come principally from experiments with protein films and powders. The principal aim is to examine the relationship between the sites of water interaction, the extent of coverage, and the enzymatic activity, thus providing a better understanding of the relationship between water and enzyme dynamics.