In Fig.2 of the article,[1]the figure caption should be“Rocking curve of the(006)peak of the Tl-1223 thin film”instead of“Rocking curve of the(003)peak of the Tl-1223 thin film”.The corresponding description of this figure should be“As shown in Fig.2,the full width at half maximum(FWHM)of the Tl-1223(006)reflection peak is only 0.58∘,which shows that the film possesses a good crystalline structure”,instead of“As shown in Fig.2,the FWHM of the Tl-1223(003)reflection peak is only 0.58∘,which shows that the film possesses a good crystalline structure”.
The voltage-biased current-voltage(I-V)characteristics of intrinsic Josephson junctions(IJJs),which are fabricated with misaligned high temperature superconducting Tl2Ba2Ca Cu2O8(Tl-2212)thin film,are investigated experimentally.Three characteristic regions in the I-V curve are observed at 47 K.In the low voltage part,the current firstly increases and then decreases slowly with increasing the biased voltage,which is shown as a bump.In the next region,the current slightly increases with increasing the biased voltage until a sudden decrease of the current appears.Thereafter,branch structure forms with increasing the voltage on the I-V characteristic.The influence of the self-heating on the I-V characteristics is investigated and the temperature dependence of the I-V characteristics is measured to explore these characteristics in detail.
WANG PeiXIE WeiHU LeiLIU XinJI LuHE MingZHANG XuZHAO XinJieYAN ShaoLin
We report the circuit simulations and experiments of millimeter-wave radiation from a high temperature superconducting(HTS) bicrystal Josephson junction(BJJ) array. To study the effects of junction characteristic parameters on radiation properties, new radiation circuit models are proposed in this paper. The series resistively and capacitively shunted junction(RCSJ) models are packaged into a Josephson junction array(JJA) model in the simulation. The current-voltage characteristics(IVCs) curve and radiation peaks are simulated and analyzed by circuit models, which are also observed from the experiment at liquid nitrogen temperature. The experimental radiation linewidth and power are in good agreement with simulated results. The presented circuit models clearly demonstrate that the inconsistency of the JJA will cause a broad linewidth and a low detected power. The junction radiation properties are also investigated at the optimal situation by circuit simulation. The results further confirm that the consistent JJA characteristic parameters can successfully narrow the radiation linewidth and increase the power of junction radiation.
Intrinsic Josephson junctions in misaligned Tl2Ba2CaCu2O8 thin film were fabricated on LaAlO3 substrate. The temperature dependence of the critical current is investigated around liquid nitrogen temperature. In the current voltage characteristic, large voltage jump and lack of resistive branch are observed, which shows good consistency with the intrinsic Josephson junctions. By analyzing the large gap voltage in the curve, great suppression of the energy gap is found. Through discussing the temperature dependence of the gap voltage in liquid nitrogen temperature, it is shown that this phenomenon can be caused by the non-equilibrium quasiparticle injection. The temperature influence on the excess current also confirms the non-equilibrium effect.
A new improved two-step method in fabricating Tl_2Ba_2 CaCu_2O_8(Tl-2212) thin films is presented in this paper. In the first process of dc magnetron sputtering, the thallium content in the precursor film is largely increased by adjusting the ratio of thallium in the sputtering targets. After the second annealing process in the absence of additional thallium pellets or powder source, high-quality Tl-2212 thin films can be obtained. The proper content of thallium in the precursor film provides a relatively stable atmosphere to guarantee the growth of Tl-2212 film. This method avoids the repeated production of the thallium pellets in the post-annealing process, the repeatability and controllability of the experiment are greatly improved. X-ray diffraction(XRD) scans show that all of the sharp peaks of the sample films can be assigned to the(00 l) peaks of Tl-2212 phase. The highest superconducting critical temperature(Tc) of the films is 105 K and the critical current density(Jc) can achieve 1.93 MA/cm2 in zero magnetic field at 77 K for a 600 nm film.
Intrinsic Josephson junctions in misaligned Tl2Ba2CaCu2O8 thin film were fabricated on LaAlO3 substrate. The temperature dependence of the critical current is investigated around liquid nitrogen temperature. In the current voltage characteristic, large voltage jump and lack of resistive branch are observed, which shows good consistency with the intrinsic Josephson junctions. By analyzing the large gap voltage in the curve, great suppression of the energy gap is found. Through discussing the temperature dependence of the gap voltage in liquid nitrogen temperature, it is shown that this phenomenon can be caused by the non-equilibrium quasiparticle injection. The temperature influence on the excess current also confirms the non-equilibrium effect.
