مرکز منطقه ای اطلاع رساني علوم و فناوري - Study of Dielectric Properties of Oxygen-Postannealed <formula formulatype="inline"> <img src="/images/tex/20847.gif" alt="\\hbox {Cu}_{0.5} \\hbox {Tl}_{0.5}\\hbox {Ba}_{2}\\hbox {Ca}_{2}(\\hbox {Cu}_{3 \\hbox {-} {y}}\\hbox {M}_{y})\\hbox {O}

Title :

Study of Dielectric Properties of Oxygen-Postannealed $\\hbox {Cu}_{0.5} \\hbox {Tl}_{0.5}\\hbox {Ba}_{2}\\hbox {Ca}_{2}(\\hbox {Cu}_{3 \\hbox {-} {y}}\\hbox {M}_{y})\\hbox {O}_{10\\hbox </div> </div> <div class='row'> <div class='leftDiv labelDiv col-xs-4 col-sm-2 fullRecLabelEnglish'>Author : </div><div class='valueDiv leftDirection leftAlign col-xs-8 col-sm-10 fullRecValueEnglish'>Mumtaz, M. ; Khan, N.A. ; Khan, Sharifullah</div> </div> <div class='row'> <div class='leftDiv labelDiv col-xs-4 col-sm-2 fullRecLabelEnglish'>Author_Institution : </div><div class='valueDiv leftDirection leftAlign col-xs-8 col-sm-10 fullRecValueEnglish'>Dept. of Phys. Fac. of Basic & Appl. Sci., Int. Islamic Univ., Islamabad, Pakistan</div> </div> <div class='row'> <div class='leftDiv labelDiv col-xs-4 col-sm-2 fullRecLabelEnglish'>Volume : </div><div class='valueDiv leftDirection leftAlign col-xs-8 col-sm-10 fullRecValueEnglish'>23</div> </div> <div class='row'> <div class='leftDiv labelDiv col-xs-4 col-sm-2 fullRecLabelEnglish'>Issue : </div><div class='valueDiv leftDirection leftAlign col-xs-8 col-sm-10 fullRecValueEnglish'>2</div> </div> <div class='row'> <div class='leftDiv labelDiv col-xs-4 col-sm-2 fullRecLabelEnglish'>fYear : </div><div class='valueDiv leftDirection leftAlign col-xs-8 col-sm-10 fullRecValueEnglish'>2013</div> </div> <div class='row'> <div class='leftDiv labelDiv col-xs-4 col-sm-2 fullRecLabelEnglish'>fDate : </div><div class='valueDiv leftDirection leftAlign col-xs-8 col-sm-10 fullRecValueEnglish'>4/1/2013 12:00:00 AM</div> </div> <div class='row'> <div class='leftDiv labelDiv col-xs-4 col-sm-2 fullRecLabelEnglish'>Firstpage : </div><div class='valueDiv leftDirection leftAlign col-xs-8 col-sm-10 fullRecValueEnglish'>8800108</div> </div> <div class='row'> <div class='leftDiv labelDiv col-xs-4 col-sm-2 fullRecLabelEnglish'>Lastpage : </div><div class='valueDiv leftDirection leftAlign col-xs-8 col-sm-10 fullRecValueEnglish'>8800108</div> </div> <div class='row'> <div class='leftDiv labelDiv col-xs-4 col-sm-2 fullRecLabelEnglish'>Abstract : </div><div class='valueDiv leftDirection leftAlign col-xs-8 col-sm-10 fullRecValueEnglish'>The superconducting properties [onset temperature (<i>Tc</i><sup>onset</sup>) and zero-resistivity critical temperature <i>Tc</i> (<i>R</i> = 0) ] and the dielectric properties [dielectric constants (ε<i>r</i><sup>/</sup>, ε<i>r</i><sup>//</sup>), absolute dielectric loss | tan δ|, and ac conductivity (σ<sub>ac</sub>)] of oxygen-postannealed Cu<sub>0.5</sub>Tl<sub>0.5</sub>Ba<sub>2</sub>Ca<sub>2</sub>(Cu<sub>3-</sub><i>y</i>M<i>y</i>)O<sub>10-δ</sub>(M = Si, Ge, Sn; <i>y</i> = 0, 1) superconductor have been studied. The superconducting properties have been increased in all undoped and Si-, Ge-, and Sn-doped samples after oxygen postannealing. The negative capacitance (NC) has been also observed in all postannealed Cu<sub>0.5</sub>Tl<sub>0.5</sub>Ba<sub>2</sub>Ca<sub>2</sub>(Cu<sub>3-y</sub>M<sub>y</sub>)O<sub>10-δ</sub> samples. Capacitance <i>C</i> and conductance <i>G</i> of Ge-doped Cu<sub>0.5</sub>Tl<sub>0.5</sub>Ba<sub>2</sub> Ca<sub>2</sub>(Cu<sub>2</sub>Ge<sub>1</sub>)O<sub>10 - δ</sub> and Sn-doped Cu<sub>0.5</sub>Tl<sub>0.5</sub>Ba<sub>2</sub>Ca<sub>2</sub>(Cu<sub>2</sub> Sn<sub>1</sub>) O<sub>10-δ</sub> samples have been increased after oxygen postannealing. In contrary, the values of <i>C</i> and <i>G</i> have been decreased in both the undoped Cu<sub>0.5</sub>Tl<sub>0.5</sub>Ba<sub>2</sub>Ca<sub>2</sub>Cu<sub>3</sub> O<sub>10-δ</sub> and Si-doped Cu<sub>0.5</sub> Tl<sub>0.5</sub>Ba<sub>2</sub>Ca<sub>2</sub>(Cu<sub>2</sub>Si<sub>1</sub>)O<sub>10-δ</sub> samples after oxygen postannealing. The variation of <i>C</i> and <i>G</i> depends upon the degree of polarizibility, which is associated with carrier´s density. The carrier´s density depends upon the oxygen content, which can be controlled by oxygen postannealing. The appreciable change in the dielectric properties of Cu<sub>0.5</sub>Tl<sub>0.5</sub>Ba<sub>2</sub>Ca<sub>2</sub>(Cu<sub>3-y</sub>M<sub>y</sub>)O<sub>10-;- ;</sub> samples is the indication of oxygen variation after oxygen postannealing. These studies also show that the dielectric response of Cu<sub>0.5</sub>Tl<sub>0.5</sub> Ba<sub>2</sub>Ca<sub>2</sub>(Cu<sub>3-y</sub>M<sub>y</sub>)O<sub>10-δ</sub> samples is strongly temperature and frequency dependent.</div> </div> <div class='row'> <div class='leftDiv labelDiv col-xs-4 col-sm-2 fullRecLabelEnglish'>Keywords : </div><div class='valueDiv leftDirection leftAlign col-xs-8 col-sm-10 fullRecValueEnglish'>annealing; barium compounds; calcium compounds; copper compounds; dielectric losses; dielectric polarisation; electrical conductivity; electrical resistivity; germanium compounds; high-temperature superconductors; permittivity; silicon compounds; superconducting transition temperature; thallium compounds; tin compounds; AC conductivity; Cu<sub>0.5</sub>Tl<sub>0.5</sub>Ba<sub>2</sub>Ca<sub>2</sub>(Cu<sub>3-y</sub>Ge<sub>y</sub>)O<sub>10-δ</sub>; Cu<sub>0.5</sub>Tl<sub>0.5</sub>Ba<sub>2</sub>Ca<sub>2</sub>(Cu<sub>3-y</sub>Si<sub>y</sub>)O<sub>10-δ</sub>; Cu<sub>0.5</sub>Tl<sub>0.5</sub>Ba<sub>2</sub>Ca<sub>2</sub>(Cu<sub>3-y</sub>Sn<sub>y</sub>)O<sub>10-δ</sub>; absolute dielectric loss; carrier density; dielectric constant; dielectric properties; negative capacitance; onset temperature; oxygen postannealing; oxygen-postannealed superconductor; polarizibility degree; superconducting properties; zero-resistivity critical temperature; Capacitance; Conductivity; Dielectric constant; Reservoirs; Silicon; <formula formulatype=$ $hbox{Cu}_{0.5}hbox{Tl}_{0.5}hbox{Ba}_{2}hbox{Ca}_{2}( hbox{Cu}_{3 hbox{-} {y}}hbox{M}_{y})hbox{O}_{10 hbox{-} delta}$ superconductor; dielectric properties; postannealing;