Third-order intermodulation in two-pole X-band HgBa2CaCu2O6+δ microstrip filters

Abstract

Third-order intermodulation is studied in two-pole X-band high-temperature superconducting (HTS) HgBa2CaCu2O6+δ microstrip filters at >77K. The third-order intercept (IP3) of the HgBa2CaCu2O6+δ filters is consistently higher than that of the YBa2Cu3O7 filter of the same geometry in this temperature range. At 110K, the IP3 of 38dBm remains for the Hg-1212 filters, the best so far achieved at T>100K. The dc critical current density Jc and the rf one JIP3 derived from the IP3 have a similar reduced temperature dependence, suggesting that the magnetic vortex depinning in HTS materials dominates the microwave nonlinearity at elevated temperatures.

A comparative study of microwave power handling capabilities of Tl-1212 and Hg-1212 superconducting microstrip lines

“…The coincidence of the P c -t curves of the '1212' isomorphic pair suggests that anisotropy of the electronic structure plays a critical role in determining the temperature dependence of the microwave power handing capability. It is worth mentioning that our earlier research on YBCO, Hg-1212 and Tl-2212 has qualitatively demonstrated a correlation between the microwave power handing capability with the anisotropy of the electronic structure [5,6]. Basically, the least anisotropic YBCO has the least susceptibility to t, while the highest anisotropic Tl-2212 experiences the most susceptibility to t. The result shown in figure 2 provides a quantitative demonstration of the correlation between the microwave power handing capability with the anisotropy of the electronic structure of the HTSs.…”

“…Consequently, the '1212' pair shares the same reduced temperature (t = T /T c ) dependence of critical current density J c and irreversibility [3,4]. In a recent study of the microwave nonlinearity in several high temperature superconductors (HTSs) including YBa 2 Cu 3 O 7 (YBCO), Tl 2 Ba 2 CaCu 2 O 8 (Tl-2212) and Hg-1212, the J c and the rf critical current density J IP3 derived from the third-order intercept (IP3) was found to follow a similar t-dependence for each of the three HTSs in the elevated temperature range near T c , suggesting that the magnetic vortex depinning in HTS materials dominates the microwave nonlinearity at elevated temperatures [5,6]. Qualitatively, this observation agrees well with the recent theoretical discussion on the origin of the microwave nonlinearity [7].…”

Jcenhancement in Tl2Ba2CaCu2Oxthin films by introduction of CeO2nanodots on substrates

“…From some recent research on microwave nonlinearity of HTS films, the HTS films' microwave power handling or the third intermodulation were related to the films' magnetic vortices pinning strength [20][21][22]. In microwave fields, Tl-2212 films have been widely used, the weak pinning strength will influence the performance of Tl-2212 film made devices, and the enhancement of J c on Tl-2212 films is important and necessary.…”

Superconductivity of 132 K in HgBa2Ca2Cu3O8+δthin films fabricated using a cation exchange method

“…In the case of using Tl-2212 as the precursor, the double Tl-O layers in Tl-2212 collapse into one Hg-O layer during the cation exchange, resulting in a shortening of the c axis by 14% from 2.96 nm for Tl-2212 to 1.27 nm for Hg-1212. Using epitaxial Tl-1212 and Tl-2212 films as precursors, epitaxial Hg-1212 thin and thick films have been obtained on dielectric and metal substrates for both electronic [12][13][14][15][16] and electrical devices applications [17,18]. Furthermore, the cation exchange between Hg-1212 films and Tl-1212 (or Tl-2212) films has been found to be fully reversible [10,19].…”