Title :
Growth of Hg0.8Pb0.2Ba2Ca2 Cu3O8+δ thick films on Ag using a modified process route
Author :
Su, Jianhua ; Sastry, P.V.P.S.S. ; Schwartz, Justin
Author_Institution :
Nat. High Magnetic Field Lab., Florida State Univ., Tallahassee, FL, USA
fDate :
3/1/2001 12:00:00 AM
Abstract :
Thick films of Hg0.8Pb0.2Ba2Ca 2Cu3O8+δ (HgPb1223) superconductor were fabricated by dip-coating Pb0.2Ba2 Ca2Cu3O7+δ precursor onto Ag and subsequently reacting in Hg vapor to form the superconducting phase. It was found that by “burying” the films in precursor powder during the reaction, increased HgPb1223 phase purity and increased size of aligned grain colonies were obtained. Such microstructural improvements lead to wider magnetization hysteresis. The optimum superconducting transition temperatures of 133 K were observed in these films. The results showed that this process has a positive influence on the formation and growth of HgPb1223. A pre-pressing process enabled the growth of HgPb1223 grains with relatively dense microstructure and improved connectivity. The resulting films exhibited a transport Jc value of at least 1.5×103 A/cm2 at 4.2 K in a zero magnetic field
Keywords :
barium compounds; calcium compounds; critical current density (superconductivity); crystal microstructure; grain growth; high-temperature superconductors; lead compounds; magnetic hysteresis; materials preparation; mercury compounds; powder technology; superconducting thin films; superconducting transition temperature; thick films; 133 K; 4.2 K; Ag; Ag substrate; Hg; Hg vapor; Hg0.8Pb0.2Ba2Ca2Cu 3O8+δ; Hg0.8Pb0.2Ba2Ca2Cu 3O8; HgPb1223; Pb0.2Ba2Ca2Cu3O 7+δ precursor; Pb0.2Ba2Ca2Cu3O7 ; aligned grain colonies; dense microstructure; dip-coating; film growth; grain growth; improved connectivity; magnetization hysteresis; microstructural improvements; modified process route; phase purity; pre-pressing process; precursor powder; superconducting transition temperature; thick films; transport Jc value; Dip coating; Lead; Magnetic hysteresis; Magnetization; Mercury (metals); Microstructure; Powders; Superconducting films; Superconducting transition temperature; Thick films;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
