Transport properties of (Hg, M)-12(n-1)n (M = Re, Mo; n=2, 3) superconducting thin films

We have successfully fabricated 200 - 500 nm thick highly c-axis oriented ( Hg, Re)-1223 and (Hg, M)-1212 (M = Re, Mo) thin films on SrTiO3 (100) subst rates by using HgO/M-Ba-Ca-Cu-O multilayer precursor films prepared by puls ed laser deposition. Their electrical transport properties in magnetic fiel ds less than 7 T are investigated using 5 - 50 mu m wide bridges patterned by means of electron-beam lithography and ion milling without using water. The (Hg, Re)-1223 film exhibits a T-c (zero) of 127.5 K and a J(c) value at 77 K of 1.5 and 0.2 x 10(6) A/cm(2) in a self-field and 1 T field, respect ively. Higher J(c) values below 100 K are observed for (Hg, M)-1212 (M = Re , Mo) films with better crystallinity and surface morphology than the 1223 film in spite of their lower T, (zero) of 115-122 K. The (Hg, Re)-1212 film exhibits the highest J(c) values of 5, 1.5, and 0.4 x 10(6) A/cm(2) at 77 and 100 K in a self- field and at 77 K in 1 T field, respectively. The irre versibility field above 77 K evaluated from the resistive transitions of th ese films is found to be substantially higher than those for undoped Hg-121 2 and TI-1223 thin films.