BackSuperconductors

Gelest, Inc. offers a wide range of metal alkoxides and diketonates for use in forming metal oxide superconductors. Alkoxide precursors can be used for making mixed-metal superconductors by sol-gel routes. Volatile precursors are used in MOCVD preparations of thin film superconductors. Exciting developments in the field of high temperature superconductors have lead to many new materials being investigated.

The key structural unit in high critical temperature (Tc) superconductors is the CuO2 plane. This two-dimensional plane consists of divalent copper and oxygen ions. There is a general consensus that this plane plays an essential role in the formation of the Copper pairs, and therefore, in the appearance of superconductivity itself. Divalent copper ion is a d9 ion because of its strong electron-electron interaction, and the ninth electron tends to be localized on each copper site, resulting in semiconducting or insulating behavior in the CuO2 plane, and so its ground state is not superconducting but is antiferromagnetic. Superconductivity appears if this plane is doped with holes (or electrons), and the formal valence of the copper ion deviates from 2+. There is an optimum doping level for holes (electrons). A high Tc superconductor should, therefore, have at least two structural features:-(i) a layered structure based on the CuO2 plane, and (ii) in addition to the CuO2 plane, a certain structural block, called a charge reservoir, where a proper number of carriers are created and doped into the CuO2 plane. A simple way to dope carriers into the CuO2 plane in the infinite-layer compound is through heterovalent metal substitution. For instance, an n-type superconductor with electrons as carriers is formed by partial replacement using a trivalent metal such as lanthanum, barium, strontium or yttrium.

Listed below are some popular examples of metal oxide precursors, and Gelest, Inc. offers many other precursors for the metal oxides used in superconductors.

AKB121 Barium isopropoxide, 20% in isopropanol
AKB144 Barium 2,2,6,6-tetramethyl-3,5-heptanedionate
CXBA080 Barium trifluoroacetate
CXBI040 Bismuth 2-ethylhexanoate
AKC163 Calcium hexafluoropentanedionate
AKC172 Calcium 2,2,6,6-tetramethyl-3,5-heptanedionate
AKC253 Copper hexafluoropentanedionate
AKC262 Copper 2,2,6,6-tetramethyl-3,5-heptanedionate
AKC248 Copper II dimethylaminoethoxide
AKL430 Lanthanum 2,4-pentanedionate
AKS793 Strontium methoxypropoxide, 18-20% in methoxypropanol
AKY927 Yttrium methoxyethoxide, 15-18% in methoxyethanol
AKY932 Yttrium 2,2,6,6-tetramethyl-3,5-heptanedionate

Double metal alkoxides

DBAY060 Barium Yttrium double metal alkoxide