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AC losses on stabilized Rutherford cables are measured and reported.

Superconducting properties obtained during an optimization study of rapid-heat processing of jelly-roll (JR) Nb[subscript 3]Al multifilamentary wires are reported and discussed.

Field error and F-J stability issues are examined in the context of magnetization as the critical defining parameter for strand in precision dipole applications.

Compaction and variation of core width effects on coupling loss and contact resistance in cored stabrite cables are examined.

A rapid ohmic-heating and quenching method was used to process Nb3A1 in optimization studies.

Transformed jelly-roll Nb3A1 multifilamentary wires were studied to determine their superconducting properties and rapid heating condition.

Untwisted multifilamentary superconducting tapes were measured for AC loss using a vibrating sample magnetometer.

Rutherford cable wound with Cu-stabilized jelly roll unplated Nb3A1 strand was studied and calorimetric measurements of AC loss and interstrand contact resistance were undertaken.

The results of electric measurements of coupling losses in five-layer stacks of niobium-tin Rutherford cables that have stainless steel (SS) cores are presented. The study was conducted with the applied transverse magnetic-field in both a parallel and normal orientation to the cable's plane. The theoretical results indicate that the face-on inter-strand coupling loss measured in the SS-cored cable is determined primarily by the conductivity and thickness of both the SS core and the outer bronze region.

Research was conducted to examine the low coupling loss core-strengthened Bi:2212/Ag Rutherford cables. The winding and testing of three model cables were carried out. The emphasis of the study was on the calorimetrically measured AC loss results for the model Bi:2212/Ag cables which were compared to those of core-type Nb3Sn- and NbTi cables. Results illustrate that Bi:2212/Ag Rutherford cables can have coupling losses that can be compared to those of the other core-type cables.

A modified form of the rod-in-tube method (MRT) and the conventional jelly-roll (JR) method were used in fabricating niobium-aluminum precursor strands. Warm hydrostatic extrusion was explored for use in the next phase of strand production although most of the material produced used the fully cold drawn method. Pulsed resistive heating to temperatures of 1800 to 2100 degrees C followed by either liquid-Ga quenching or radiative cooling were used to test the JR and MRT strands.

The introduction of fine multifilamentary subdivision accompanied by twisting solved the problem of flux jumping in NbTi superconducting strands 30 years ago. However, the recent advances in A15 superconductors have resulted in J(sub c) increasing at a rate faster than effective filament diameter can be reduced. The introduction of the very high J(sub c) Nb3Sn strands whose sub-elements, although fully bridged, are still capable of being reduced in size is used to address the problem.

The conventional jelly roll method with two Niobium-aluminum (Nb-Al) volume ratios, 3:1, and 5:1, were used to fabricate Nb-Al precursor strands. The mono-elements were restacked in 7-, 19- and 36-core arrangements and drawn down to wires with 0.4 mm and 0.8 mm diameter. The wires were then resistively heated and allowed to cool by radiation plus lead conduction or by quenching in liquid gallium. The best results obtained were for a 5:1 Nb:Al volume ratio sample Ga quenched from 2000 degrees C.

The alternating current (AC) losses of stabrite-coated Rutherford cables for the Large Hadron Collider winding with applied fields directed either parallel or perpendicular to the broad face were subjected to calorimetric and magnetic measurements. Results show that a thin metallic or insulating core in the cable will reduce face-on oriented AC losses by a factor of 10. Suppressed face-on losses may also be controlled by changing the internal or external compaction levels.

A previously develop model for hysteretic loss and induced magnetization bridging was extended to include metallurgical bridges' inhomogeneous morphologies. The anisotropic continuum model presented a dimensionless parameter representing the area-fraction of bridged matrix material perpendicular to the filamentary axis. The parameters were then used to describe the bridging intensity.

The proximity effect coupling in superconducting multifilamentary strands was subjected to conventional magnetization measurements. A previously-developed approach was then employed for coupling strength quantification in terms of proximity effect coupling supercurrent. Results show that differences in the filament/matrix interface's properties cause the magnetic field field variations measured.

The ac losses of 11-strand Rutherford cables wound from strands coated with insulating or resistive metals have been examined via magnetic, calorimetric, vibrating sample magnetometric and cable diamond simulator measurements. The results that strands may be deoxidized and that strand coatings improve the contact resistances of un-oxidized strands. These underscored the role of strands' surface condition in inducing ac losses.

The results from the second round of the Versailles Project on Advanced Materials and Standards' intercomparison of low-frequency ac loss measurements are reported. The activity involved the round-robin testing of two sets of multifilamentary NbTi strands containing either a copper or a cupronickel matrix. In addition, a supplementary round-robin test was carried out to distinguish errors due to individual sample fabrication.

The magnetic hysteresis loops of several materials were quantified at 4.2 K to evaluate their applicability as lumped passive elements in the ferromagnetic compensation of axial field distortions in superconducting magnets. Specifically, the impact of demagnetization and cold work on the hysteresis loops of iron, nickel and nickel-copper alloys of different geometries were examined.

Resistance-ratio measurements are carried out to determine the effect of chrome inclusions on the electric properties of Nb3Sn multifilamentary superconducting strands. Results suggest that chromium plating retards the ingress of oxygen during reactive heat treatment, preventing high resistance ratio development. Chromium also diffuses in itself to degrade the resistance ratio.

Magnetic measurements and direct current susceptibility of three different alloys reveal that the properties of the alloys depend on nickel addition only to a small extent. The three alloys consist of nominal compositions of Cu-15% Ni, Cu-1% Mn and Cu-1% Mn-15% Ni. The magnetic measurements and susceptibility are determined by a Curie-type balance in the temperature range of 77.2 Kelvin to room temperature. The results are investigated with respect to the addition of Ni to the Cu-Mn alloys.

Atheoretical study helps derive expressions for determining effective magnetization creep rate for finite size superconductive samples with anisotropic U(o)s and J(c)s. The effective creep rate lies between two creep rates associated with two orthogonal directions. Sample geometry exhibits a strong influence on the effective creep rate. These expressions help determine the creep rates of proximity effect linked multifilamentary NbTi/Cu composites and untwisted samples of different lengths. Interfilamentary spacing and other factors that affect PE exhibit a strong influence on creep rate in both twisted and untwisted strands.

Multifilamentary superconducting strands with copper and copper-manganese matrices were subjected to tests to determine their transverse and longitudinal resistivities. The measurements were carried out on conductors with up to 5000 niobium titanium filaments. The results highlighted the relationships between size-, proximity- and current path effects and their impact on resistivity.

An experiment to study the effect of cabling geometry on proximity effect (PE) magnetization in multifilamentary superconducting cables was carried out. It involved the construction of oval and helical coils using two types of niobium titanium filaments embedded in a copper matrix with 2.0- and 6.0-micrometer diameters. The results, which were obtained via magnetometer measurements, revealed the presence of PE magnetization and creep.

A standard Bloch-Gruneisen (B-G)-based connectivity model was applied to experimental data on binary and heavily doped Mg[B.sub.2] samples as well as published resistivity data to determine the highest attainable [J.sub.c] in a given class of samples. The results from calorimetric measurements that probed the homogeneity of the doped samples in terms of the roundness of the electronic specific heat jump near [T.sub.c] are also discussed.

Magnetoresistivity and critical current density Jc, as a function of temperature and field, are studied for Bi2Sr2Ca2Cu3O10 single crystals grown using the traveling solvent floating zone technique. Analysis of resistive transition broadening revealed that thermally activated flux flow is found to be responsible for the resistivity contribution of the vicinity of T(sub c).

YBa2Cu3O7 films were fabricated by pulsed laser deposition on SrTiO3 (100) single-crystal substrates, whose surfaces were modified by the introduction of Ag nanodots. Microstructure investigations indicated that the crystallinity and the ab alignment gradually improved, as the number of Ag nanodots increased.