Thickness Dependence of Ti Buffer Layers for Fabricating As-Grown <formula formulatype="inline"><tex>${\rm MgB}_{2}$</tex></formula> Films

Systematic characterization of upper critical fields for MgB2thin films by means of the two-band superconducting theory

“…It was revealed that the c-axis of the MgB 2 is oriented in a perpendicular direction to the film surface. Especially, film #4 is found to have an excellent alignment with the in-plane orientation [20].…”

“…Four MgB 2 films were prepared by Iwate group using an MBE apparatus with the co-evaporation conditions of low deposition rate in ultrahigh vacuum without post annealing process 18,19,20 . Two of them were deposited on MgO (100) (#1) and Si (111) (#2) substrates at 200…”

“…Six as-grown MgB 2 thin films were used in the magnetoresistance measurements. Four MgB 2 films were prepared by the Iwate group using an MBE apparatus with the co-evaporation conditions of a low deposition rate in ultrahigh vacuum without post-annealing [18][19][20]. Two of them were deposited on MgO(100) (#1) and Si(111) (#2) substrates at 200 • C and the others were deposited on Ti buffer layers on ZnO(0001) substrates at 200 • C. The difference of the latter two films is the thickness of the Ti buffer layers; one is 10 nm (#3) and the other is 50 nm (#4).…”

Ambient temperature epitaxial growth of MgB2thin films with a Mg buffer layer

“…In particular, among these bilayer films, MgB 2 =Ti films that showed a sharp superconducting transition at T c = 36 K were obtained by growth at the lowest temperature of 200 °C. 15) However, this temperature is higher than the applicable temperature limit for a standard organic resist. Therefore, a lift-off-like process using an inorganic material as a resist, 16) Ar ion milling, 17) or focused ion beam milling 18) has been applied to fabrication of MgB 2 nanowire structures.…”

“…12) Some studies have attempted to perform low-temperature growth using epitaxial buffer layers with good lattice matching, such as AlN (1.9%), 13) TiZr (3.6%), 14) and Ti (4.1%). 15) The in-plane axis of MgB 2 tends to align with that of the buffer layer when the substrate temperature remains low during the entire process. In particular, among these bilayer films, MgB 2 =Ti films that showed a sharp superconducting transition at T c = 36 K were obtained by growth at the lowest temperature of 200 °C.…”