Some Aspects of Liver Iron Stores Measurement with the SQUID System

Abstract. Direct method of measurement liver iron stores using SQUID gradiometer system is presented. A method for correction of the results, which should be applied depending on the size, shape of the liver and its position against the sensor is given. The possibility of using this noninvasive method in clinical practice is presented

Study of effect of Sn doping of EuBa2Cu3-xO7-δ compound on superconducting properties by contactless methods

Effect of Sn addition on structural and superconducting properties in EuBa2Cu3O7-δ (Eu-123) compound was studied using XRD and SQUID magnetometric measurements. Transition process from normal to superconducting state was analyzed by the measurement of temperature change of the magnetic moment of the combined ZFC and the remanence technique beside the usual ZFC and FC ones. Samples of the nominal composition EuBa2Cu3-xSnxO7-δ with x ranging from 0.0 to 0.2 were prepared by the solid state reaction technique from Eu2O3, BaCO3, CuO and SnO2 precursors. The increasing Sn-content deteriorates the superconducting properties of the Sn doped samples

Experimental Liver Iron Measurement with the SQUID Gradiometer System

An experimental system for noninvasive measurement of the iron stores in the liver of living human organism has been designed and realized. This system enables to test the presence and to determine the iron concentration in this organ. The principle of operation is based on measurement of small response (magnetic moment) of the paramagnetic protein ferritin to the applied magnetic field on the complex diamagnetic background of other body organs. The experiment was performed by modified SQUID system with the 2nd order gradiometer. At present, the sensitivity of the system is 1 mg Fe per gram of the wet liver, which from the point of view of clinical diagnostics, enables to indicate the state of the liver iron overload, e.g., in hemochromatosis and hemosiderosis

Identification of single-domain structures in the system YBa 2 Cu 3 O 7-δ -Ag by magnetization measurements

Abstract The magnetization methods were used in study of effect of Ag doping on the structural and superconducting parameters in two series of melted and highly textured samples of the system (YBa 2 Cu 3 O 7−δ ) 1-x (Ag 2 O) x . The x concentration level of the first series ranged from 0 to 10 wt % and the second one from 0 to 3.6 wt % Ag 2 O. By means of the SQUID magnetization measurements the optimum Ag 2 O doping level ranged from 1.6 to 2.8 wt %. These methods led to optimization of conditions in preparation of single-domain samples. From the secondary precipitated CuO phase and from the appearance of Ag component the solubility limit of Ag in solid solution YBa 2 Cu 3−y Ag y O 7−y/2−δ was found

Influence of synthetic processing on the magnetic properties of superconducting YBa2Cu3O7/Ag composites

AC magnetisation measurements and scanning electron microscopy data obtained by four different means of synthesis of YBa2Cu 3O7/Ag composites show that the percolation threshold of silver metal is crucially dependent on the method of preparation. When the sintering is performed under conditions close to the eutectic melt formation, the percolation threshold of silver is shifted to lower values. At 20 wt% Ag addition and above, the silver layer precipitates at grain boundaries and fully interrupts the intergranular superconducting link

Effects of Europium-Barium Nonstoichiometry in EBCO123 Systems on Transition and Magnetization Properties

We studied the effects of Eu-Ba nonstoichiometry in two series of $Eu_{1+x}Ba_{2-x}Cu_3O_{7-δ}$ and $Eu_{1-x}Ba_{2+x}Cu_3O_{7-δ}$ samples on transition, structural, and magnetic properties. The samples with the nominal composition of 0≤x≤0.07 were synthesized by the solid-state reaction method from $Eu_2O_3,$ $BaCO_3,$ and CuO precursors and sintered at 1050°C for 72 h in flowing oxygen. All the samples show the values of critical temperature $T_c$, volume density ρ, and maximum volume magnetization $M_\text{max}$ higher than 90 K, 6.3 g $cm^{-3}$ and $10^4 Am^{-1}$, respectively, except for x = 0.07 samples. The Eu-Ba nonstoichiometry in the two series shows different effects on transport, magnetization hystereses, and intergrain properties of the samples

Magnetometric Measurements of Low Concentration of Coated Fe3O4Fe_{3}O_{4} Nanoparticles

A modified RF SQUID system with the $2^{nd}$ order gradiometer has been tested for the purposes of detecting the magnetic nanoparticles as potential carriers of biological medicament. The paper presents basic information about the sensitivity of the system and its use for quantification of low concentration of coated $Fe_{3}O_{4}$ magnetic nanoparticles. Model measurements provided information that enabled us to define the parameter influencing the experimental results. The volume of the biological object and its distance from the antenna appear to have the significant influence on the measurement accuracy

Effects of Gd/Ba Nonstoichiometry in Gd1+xBa2−xCu3O7−δGd_{1+x}Ba_{2-x}Cu_{3}O_{7-δ} on Superconducting and Magnetic Properties

Effects of slight nonstoichiometry in $Gd_{1+x}Ba_{2-x}Cu_{3}O_{7-δ}$ compounds on superconducting and magnetic properties were studied. The series of single-phase samples of $Gd_{1+x}Ba_{2-x}Cu_{3}O_{7-δ}$ with composition deviation x from the stoichiometric value of 0 to 0.1 and to -0.1 were synthesized by the solid-state reaction method from $Gd_{2}O_{3}$, $BaCO_{3}$ and CuO precursors, sintered at the temperature of ~ 1000°C in flowing oxygen and annealed at 450°C for 24 h

Magnetic Properties of YBa2\text{}_{2}Cu3\text{}_{3}O7−δ\text{}_{7-δ} Melt Textured Samples Prepared by Powder Melting Process and Quench and Melt Growth Techniques

The microstructure and magnetic properties of the melt textured YBa$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{7-δ}$ samples prepared by the powder melting process, in which Y$\text{}_{2}$Cu$\text{}_{2}$O$\text{}_{5}$ and BaCuO$\text{}_{2}$ were used as precursors, and those prepared by the quench and melt growth method are described and compared. The lattice parameters and T$\text{}_{c}$ values for the samples prepared by the both techniques were similar. The penetration and the spatial distribution of the magnetic flux in the superconducting samples was imaged by means of a field-mapping device using a Hall probe. In the range of low magnetic fields up to 820Am$\text{}^{-1}$ no significant differences in penetration of magnetic flux between the samples prepared by the powder melting process and the quench and melt growth were observed. The mapping could not resolve any grain boundaries, single grains and structural defects. By the ac and virgin volume magnetisation characteristics, which were measured in the zero-field cooled condition by a 2nd order SQUID gradiometer, no weak links were identified. Better magnetic properties of the quench and melt growth samples in high magnetic fields can be explained by the differences in microstructure and/or by the risen content of the finely dispersed 211 and Pt containing phases. The increase factor in magnetisation is about 2.5. Some aspects of the Bean model for textured YBa$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{7-δ}$ samples are discussed

Study of light nonstoichiometry in Eu-Ba-Cu-O systems

We studied effects of light Eu-Ba nonstoichiometry in Eu-Ba-Cu-O superconducting compounds on their transition, structural, and magnetic properties. Two series of Eu1+xBa2-x Cu3O7+delta and Eu1-x Ba2+xCu3O7+delta samples with x = 0, 0.01, 0.02, 0.04, 0.05, 0.07 and 0.1 were synthesized by the solid-state reaction method from Eu2O3, BaCO3 and CuO precursors and sintered at 1050 degrees C for 72 h in flowing oxygen. Structural, transition, and magnetic properties were investigated by means of X-ray diffraction, resistance, mutual inductance, magnetization and optical measurement methods. The Eu-Ba nonstoichiometry in the two series results in different effects on transport, magnetization, grain, intergrain and microstructure properties of the samples in relation to the substitution level of x. All the samples show the values of critical temperature T-c, volume density rho, and maximum volume magnetization M-max higher than 91 K, 6.4 g cm(-3) and 10(4) Am-1, respectively