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Several tests are conducted to demonstrate the use of magnesium diboride [MgB.sub.2] for various applications of superconducting fault current limiters (SFCL). The analysis shows that [MgB.sub.2] can be easily cooled with commercial cryocolers and hence can be easily used for future SFCL applications.

The various effects of the two-stage heat treatment on superconducting properties for in-situ [MgB.sub.2X] tapes that are prepares using Mg flakes, are being explained. The two-stage heat treatment is found to enhance the core density, as well as the inter-granular connectivity of these tapes.

The enhancement of the critical current density ([J.sub.c]) in various nano-[Si.sub.3][N.sub.4] doped [MgB.sub.2]/Fe tapes that are prepared by a short pre-annealing and intermediate rolling process, is being studied. The process enhances the value of [J.sub.c] only because of the increasing core density and connectivity of the tapes.

The study presents an analysis of the superconducting properties of [Mg.sub.2]Cu-doped [MgB.sub.2] wires with several metal sheaths. These wires come cheap, in addition to providing high critical temperature and hence can be used for various fusion reactor applications.

The various methods employed for the fabrication of [MgB.sub.2] or Mg and aluminum tapes are being discussed. The indium (In) and Sic addition to these tapes are found to enhance their properties considerably.

The strong enhancement of critical current density in [MgB.sub.2] bulk and Ni-sheathed tapes with very small [Dy.sub.2][O.sub.3] additions is being studied. The analysis shows that the N-sheathed tapes exhibit superior critical current, as compared to the pure [MgB.sub.2] powders.

The various effects of different levels of Na doping on the properties of [MgB.sub.2] bulk samples that are synthesized using the microwave-assisted technique, are being studied. The analysis reveals that the pinning energy is higher in the doped samples, as compared to the undoped ones.

Several studies and experiments are conducted for the synthesis and testing of [Mg.sub.2] tapes and bindings in DC, as well as an AC regime. The analysis shows that in spite of some degradation, these windings exhibit very high critical currents.

The thermal conductivity and its effects on the properties of bulk [MgB.sub.2] produced by infiltration of different boron powders are being studied. The analysis reveals that using highly pure large grain cylinders can improve the thermal conductivity of these bulks.

Various studies have been conducted to devise methods for the improvement of the magnetic behavior of the magnesium diboride tapes, which are produced through the ex-situ Powder-In-Tube (PIT) method. The insertion of SiC nanoparticles in the precursors is found to enhance the in-field properties of the tapes.

The in-situ synchrotron x-ray powder diffraction is employed to study the kinetics of [Mg.sub.2] formation from a mixture of boron and magnesium powder. The quality of the diffraction pattern can be easily improved by using lead absorber ring or aperture.

The magneto-optical studies of the polycrystalline [Mg.sub.2] bulks manufactured by different processes are used to analyze the relationship between critical current properties and the microstructures. The current limiting factors have a great correlation with the microstructures.

The analysis explains the effects of the nanoparticle doping on electrical properties of [MgB.sub.2] bulks and wires, which are obtained by the reactive Mg liquid infiltration (RLI) technique. It is found that the addition of SiC nanoparticles improves the irreversibility, as well as the upper current field of the wires.

The experiments present a magnetic characterization of the [Mg.sub.2] superconducting hollow cylinder at variable temperatures up to the critical temperature ([T.sub.c]). The analysis reveals that an increase in the temperature and in the magnetic field leads to a strong decrease in the [eta]-values.

The characterization of Mg[B.sub.2] thin films and SIS junctions fabricated under various deposition conditions which exhibits a trilaer film to have a nitrided and oxidized region at the insulator portion is described.

Various x-ray diffraction experiments are employed to study the microscopic-scale structures of 0.72Pb([Mg.sub.1/3][Nb.sub.2/3])[O.sub.3]-0.28PbTi[O.sub.3] relaxor ferroelectrics in a high external dc field during phase transition. The results clearly prove that a change in the temperature also leads to a major change in the dominating cluster's orientation, as well as their interaction direction.

A model is proposed to explain the behavior of the volume pinning forces in parallel and perpendicular orientations of the magnetic field accounting for the texturing gradient between the center of the filament and the Mg[B.sub.2]/Fe interface. The degree of texturing of Mg[B.sub.2]/Fe ex situ tapes is investigated by magnetic measurements and x-ray diffraction.

The electronic structures of two silole derivatives 2,5-bis(6-(2',2'-bipyridyl))-1,1-dimethyl-3,4-diphenyl silacyclopentadiene (PyPySPyPy) and 2,5-di-(3-biphenyl)-1, 1-dimethyl-3,4-diphenylsilacyclopentadiene(PPSPP) at their interfaces with Mg were investigated, using spectroscopic methods. It was found that deposition of either PyPySPyPy or PPSPP onto a Mg film resulted in an abrupt interface and the formation of two gap states, assigned to a charge transfer complex.

A study prepared Mg2NiH4 thin films by activated reactive evaporation in a molecular beam epitaxy system equipped with an atomic hydrogen source. The optical band gap of the in situ deposited Mg2NiH4 hydride, 1.75 eV, is in good agreement with that of Mg2NiH4 which was formed ex situ by hydrogenation of metallic Pd capped Mg2Ni films.

A circularly polarized ultraviolet (UV) laser pulse might be used to excite a unidirectional valence-type electronic ring current in an orientation molecule, within the pulse duration of a few femtoseconds. The mechanism is demonstrated by quantum model simulation for population transfer in the model system, Mg-porphyrin, and the net ring current generated by the laser pulse is stronger than any ring current with present technology.

A study of the effect of Mg doping on the superconducting properties of Cu(sub 1-x)Tl(sub x)Ba(sub 2)Ca(sub 3-y)Mg(sub y)Cu(sub 4)O(sub 12-delta) is presented. It is observed through softening of Cu(2)-O(sub A)-Tl apical oxygen mode that improved interplane coupling is a possible source of enhancement of T(sub c)(R=0) to 131 K.

Phases and domains in a (110)-cut Pb(Mg1/3Nb2/3)(sub 0.74)Ti(sub 0.26)O3 single crystal are investigated as functions of temperature and dc electric (E) field by dielectric permittivity, polarizing microscopy and electric polarization. The unpoled sample has a dominant rhobohedral (R) phase, which coexists with monoclinic (M) phase domains at room temperature.

The nitrogen coimplantation characteristics in the Mg- and Be-implanted GaN with different dopant concentration ratios are investigated. The results reveal that the selective-area N coimplantation with Mg and Be atoms into GaN is an effective method to enhance the p-type conductivity and to improve the p-type Ohmic contact resistance.

The reaction of dialkylmagnesium with alkylzinc triisopropylsilylamide leads to a ligand exchange reaction and the formation of magnesium bis(triisopropysilylamide) that can be crystallized after the addition of 1,2-bis(dimethylamino)ethane (TMEDA). The tetracoordinate nitrogen atoms show rather long Mg-N bond lengths of 210.7 pm due to the bridging position of the triisopropylsilylamide anion.

0.7PbMg1/3(Nb0.9Ta0.1)2/3O3-0.3PbTiO3 (PMNT-PT) ceramic is prepared with solid-state reaction method and is characterized. Ta-doped PMN-PT exhibits quite high pyroelectric current density, 108 nA/cm(super 2).

The volatile metal-organic precursors tris(2,2,6,6-tetramethyl-3,5-heptanedionato(indium(III) [In(dpm)(sub3)], bis(2,4-pentanedionato)tin(II) [Sn(acac)(sub2)], and bis(2,2,6,6-tetramethyl-3,5-heptanedionato)(N,N,N'N'-tetramethylenediamine)magnesium(II) [Mg(dpm)(sub2)(TMEDA)] is used to grow Mg- and Sn-doped In2O3 (Mgln(sub x)Sn(sub y)O(sub z), 6.0

Ion-molecule complexes of the form Mg(H2O)Ar(sub n)(super +) (n=1-8) are produced by laser vaporization in a pulsed-nozzle cluster source and are further studied with infrared photodissociation spectroscopy in the O-H stretch region. The combined spectroscopic and theoretical studies reveal the presence of multiple isomeric structures at each cluster size as the argon atoms gather around the Mg+(H2O) unit.

Structural and transport properties of MgB2/MgO and MgB2/AlN multilayers for MgB2 Josephson junctions are reported. Excellent superconducting and transport properties are obtained in the MgB2 layers in both MgB2/MgO and MgB2/AlN heterostructures.

A fabrication process for membrane-structured superconducting MgB2 neutron detectors and measurement of their dc-characteristics is reported. The membrane-structured MgB2 device showed superconductivity, namely, a T(sub c, onset) of 28.2 K, a T(sub c, offset) of 27.3 K, and an RRR of 1.18.

Coupling of acetylene, nitrile, and a titanium reagent, Ti(O-i-Pr)(sub 4)/2 i-PrMgCl, generated new azatitanacyclopentadienes in a highly regioselective manner. Their subsequent reaction with sulfonylacetylene afforded pyridyltitanium compounds when reacted with electrophiles, gave substituted pyridines virtually as a single isomer.

A study is carried out on the dielectric properties and domain structure that is measured as functions of temperature in a (001)-oriented Pb(Mg(sub 1/3) Nb(sub 2/3))(sub 0.65)Ti(sub 0.35)O(sub 3) (PMNT35%) single crystal with and without a prior dc electric (E)-field poling. Details of the phase thermal stability of (001)-cut PMNT35% crystal with and without a prior dc E-field application along [001] are revealed.

Raman spectroscopy was used to examine structural changes, particularly the formation of contact-ion pairs in supersaturated aqueous NaCH3COO and Mg(CH3COO)(sub 2) droplets at ambient temperatures. The findings indicate that the single droplets levitated in an electrodynamic balance (EDB), lost water, and became supersaturated when the relative humidity decreased.

The complex solid solution (1-x)Bi(Mg(sub 3/4)W(1/4)O(sub 3)-xPbTiO(sub 3) [(1-x)BMW-xPT] was investigated by building the ferroelectric family based on the Bi[Mg(super +3)O(sub 3)-PbTiO3 solid solutions. The phases and basic dielectric properties in a (1-x)Bi(Me'Me')O(sub 3)-xPbTiO(sub 3) system and preliminary structural phenomena are reported.

Ferroelectric domain structures of a (001)-oriented lead magnesium niobate-lead titanate tetragonal crystal is examined under cyclic bipolar electric fields. The model based on 180 degree domain switching is suggested to explain interpenetration of the domains and the withdrawal of the original domain walls.

The ferroelectric thin films have a single-crystal structure. Surface structure had a big influence on the microstructure of thin films.

Polarization reversal and domain dynamics are investigated in 0.7Pb(Mg(sub 1/3)Nb(sub 2/3))O(sub 3)-0.3PbTiO(sub 3) using a method of current transients. The kinetics of the transients are modeled to an equation of state for heterogeneous nucleation in the vicinity of random fields.

A new approach, using optimizing plasma synthesis for the fabrication of 'dirty' [MgB.sub.2] is being described. The analysis proves that the methodology used can be easily used to improve the reaction kinetics for alloying of these lattices.

The fabrication of Mg[B.sub.2] meander lines with width ranging from 250 to 500 nm by using electron beam lithography (EBL)-based technique which were observed to maintain good superconducting properties are reported.

The determination of the complete set of elastic, piezoelectric and dielectric constants of 0.67Pb([Mg.sub.1/3][Nb.sub.2/3])[O.sub.3]-0.33PbTi[O.sub.3] single crystal is reported using Brillouin scattering. The values of these determined constants are similar to the previously determined four crystal samples by using a hybrid method combining ultrasonic and resonant techniques.

The fabrication of quasiparticle and Josephson tunnel junctions are investigated based on superconducting Mg[B.sub.2] films with higher critical temperature of 39 K and the advantage of the conventional superconductors, which follows Bardeen-Copper-Shrieffer theory. The result shows that clean tunneling characteristics for Mg[B.sub.2] junctions on Si wafer with the measured superconducting energy gap values are in good agreement with theory and the feasibility of the technology.

A large decrease in the electrical resistance of the junction is observed with an applied voltage of several volts in small area ramp-type junctions. The lower resistivity can be reached using an electrode with a lower resistance.

The synthesis, structure and the persistent luminescence and up conversion photostimulated luminescence properties exhibited by the nondoped [Mg.sub.2]Sn[O.sub.4] material are analyzed. The shallow, as well as the deep traps present in the material are shown to be highly responsible for the luminescence.

The article presents a new technique, which employs the different light extraction features for the formation of down-converted light-emitting diode (LED). The methodology is shown to be extremely beneficial for the extraction of light in the conventional LED structures.

Positron annihilation and Raman spectroscopies are used for studying the defect properties of perovskite type materials ([Ba.sub.3]B' [Nb.sub.2][O.sub.9] (where B' = Mg, Zn, or Co)) with near-stichiometric compositions. The existence of an internal electric field between charged 1:1 nanoregions and the rest of material has created conditions for preferential positron annihilation that affect the obtained positron lifetime values.

Surface oxidation of the CoFe and CoFeB bottom electrodes is detected by using magnetometry measurements of exchange bias (EB) characterizations that have included the EB field, training effect, uncompensated spin density and enhanced coercivity. The variations in the parameters are related to the surface oxidation of the bottom electrode and the annealed samples have shown evidence for an oxygen migration back to the MgO tunnel barrier by annealing.

A strong perpendicular anisotropy (PMA) is formed in an MgO/CoFeB/Pd unit structure for an MgO-based magnetic tunnel junction, where the composition and the thickness of the CoFeB layer has played a major role. The study has shown that the PMA is attributed to the bulk effect of forming a Pd-rich, Co-Pd alloy and the thick CoFeB layer is expected to reduce the template effect from the Pd layer during the annealing and increase the tunneling magnetoresistance of the MgO-based magnetic tunnel junction.

The photoluminescence spectroscopy methodology is adopted to explain the luminescence spectrum exhibited by [Cr.sup.3+] in Ca[Y.sub.2][Mg.sub.2][Ge.sub.3][O.sub.12]. The superimposed peaks observed in the spectrum are shown to broaden and then disappear with an increase in the temperature.