1 Researchers at American Telephone & Telegraph Co. 's Bell Laboratories reported they raised the electrical current-carrying capacity of new superconductor crystals by a factor of 100, moving the materials closer to commercial use.
2 The scientists said they created small changes in the crystal-lattice structures of the superconductors to raise the amount of current that single crystals could carry to 600,000 amps per square centimeter in a moderately strong magnetic field.
3 The scientists said they made the advance with yttrium-containing superconductors cooled to liquid-nitrogen temperature, or minus 321 degrees Fahrenheit.
4 Their report appears in today's issue of the journal Nature.
5 The finding marks a significant step in research on 'bulk' superconductors, which are aimed at use in wires for motors, magnets, generators and other applications.
6 Scientists had obtained even higher current-carrying capacity in thin films of the new superconductors, but have had problems increasing the amount of current that bulk crystals could carry.
7 Superconductors conduct electricity without resistance when cooled.
8 A family of ceramic superconductors discovered during the past three years promise new technologies such as cheaper electrical generation -- but only if their current-carrying capacity can be raised.
9 The AT&T advance shows how one aspect of the current-carrying problem can be overcome.
10 But 'it won't lead to imminent use' of new superconductors, cautioned Robert B. van Dover, one of the AT&T researchers.
11 He added that the current-carrying capacity of multi-crystal samples of superconductors remains too low for most practical uses because of so-called weak links between crystals.
12 Such multi-crystal materials will probably be needed for commercial applications.
13 Mr. van Dover said the AT&T team created the desired crystal changes by bombarding superconductor samples with neutrons, a process that creates some radioactivity in the samples and may not be feasible for large-scale commercial use.
14 Still, scientists breathed a collective sigh of relief about the finding, because it demonstrates how to overcome the 'flux pinning' problem that earlier this year was widely publicized as undercutting new superconductors' potential.
15 The problem involves the motion of small magnetic fields within superconductor crystals, limiting their current-carrying capacity.
16 Mr. van Dover said the crystal changes his team introduced apparently pins the magnetic fields in place, preventing them from lowering current-carrying capacity.
17 Mr. van Dover added that researchers are trying to determine precisely what crystal changes solved the problem.
18 Determining that may enable them to develop better ways to introduce the needed crystal-lattice patterns.
19 The AT&T team also is trying to combine their latest superconductor process with 'melt-textured growth,' a process discovered earlier at Bell Laboratories.
20 The combined processes may significantly raise the current-carrying capacity of multi-crystal samples.

The finding marks a significant step in research on " bulk " superconductors , which are aimed at use in wires for motors , magnets , generators and other applications .
marks a significant step in research
What makes this a significant step in research?