Incorporation of carbon into infinite-layer BaCuO2 films and formation of superconducting phase

In situ characterization of transport properties of superconducting (Cu,C)-system thin films

“…6. Relationship between T c(q=0) and temperature coefficient of resistivity (TCR) 1/q [290 K] (dq/dT) of the PLD films in this study and those of between T c(q=0) and TCR of exposed sputter-synthesis by Adachi et al [4] and MBE-grown film by Shibata et al [6]. Fig.…”

“…T c(q=0) and r [290 K] of sputter-synthesis [4,6] and MBE-grown film [8]. On the other hand, the correlation between T c(q=0) and TCR could be lost by air exposure for (Cu, C)-1201 films (see Figs Relationship between T c(q=0) and in situ normal conductivity at 290 K (r [290 K] ) of the PLD films in this study and those of between T c(q=0) and conductivity of air exposed sputter-synthesis by Adachi et al [4] and Shipra et al [8], and MBEgrown film by Shibata et al [6].…”

“…(Cu, C)Ba 2 Ca nÀ1 Cu n O x [(Cu, C)-12(n À 1)n] and CuBa 2 Ca nÀ1 Cu n O x [Cu-12(n À 1)n] are one of promising high temperature superconducting cuprate (HTS), because of the non-toxic elements and their low growth temperature, their potential for high critical temperature T c and low anisotropy [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. The multi-layered Cu-and (Cu, C)-system HTS, the presence of a widely controllable conductivity of the reservoirs, lead to novel properties that a maintenance high T c even in a heavily over-doped region [2], a controllability of the interband coupling as well as their c-axis transport, a possibility of multi-component superconductivity in multi-layered HTS with a proper interband coupling [17].…”

Preparation of films of the carbonate compound (BaxSr1−x)2Cu1+yO2+δ(CO3)1−y by molecular beam epitaxy

“…However, it can now be fabricated as a thin film by laser ablation and MBE [3]. There have also been efforts to prepare superconductor thin films containing carbonate by sputtering and laser ablation [4,5], but no investigator has succeeded in synthesizing a superconductive thin film with T c above 100 K. The carbonate superconductors with high T c have a structure with a long c axis, which seems to be the reason for the difficulty in achieving perfect crystal structure.…”

Epitaxial growth of “infinite layer” thin films and multilayers by rf magnetron sputtering

“…The obtaining of thin films both having this structure and displaying superconducting properties turned out to be very difficult. On the other hand, superconducting oxycarbonate thin films have been recently obtained 26,27 by the incorporation of C present in the deposition atmosphere or as impurity in the targets; these compounds may be regarded as IL blocks with an ordered partial substitution of CuO 2 by carbonate groups CO 22 3 , resulting in a modulation of the IL structure. It should be specially remarked here that, within the variety of reported IL multilayers with different alkaline earth cations (Ca, Sr 12x Ca x , Sr, Ba), 15,19,20,24,25 only those containing Ba 19,24 display superconducting behavior, and this is precisely the alkaline earth ion considered too large to stabilize the IL structure; it has been argued, 6,19 however, that the presence of apical oxygens might stabilize this phase and give rise to superconductivity.…”