A new method for preparing double-sided Tl-2223 HTS films
An improved two-step method for the preparation of double-sided Tl2Ba2Ca2Cu3O10(Tl-2223)high-tem-perature superconducting films on 2-inch LaAlO3(00l)substrates was proposed.The volatilization of Tl2O can be controlled without the usage of additional Tl pellets by using a special sapphire crucible.XRD analysis verified the generation of the Tl-2223 phase in the middle of the obtained film.As the film extends towards the edge,the resultant Tl-2223 phase gradually de-composes into Tl2Ba2Ca1Cu2O8(Tl-2212)phase.The downside of the film also showes a similar pattern,but its content of Tl-2212 phase is higher.SEM and AFM images show that the center of the film shows a layered structure and the edges present the particle structure.The measurement results of the 2-inch Tl-2223 film show that the critical temperature(Tc)on the up-side and downside of the film is 105 K and 101 K,the averaged critical current density(Jc)on both sides is around 1.0 MA/cm2(77 K,0 T).The microwave surface resistance(Rs)on the upside and downside of the film is 0.16 mΩ and 2.28 mΩ(77 K,10 GHz)and increases with increasing temperature,which is consistent with the two-fluid model.
Tl-2223HTS filmsCritical temperatureCritical current densityMicrowave surface resistance
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