Coating processes for YBa₂Cu₃O_7-xsuperconductor by metalorganic deposition method using trifluoroacetates

Abstract

YBa2Cu3O7-x (YBCO) films prepared by a metalorganic deposition method using trifluoroacetats (TFA-MOD method) with spin coating have excellent properties: a critical current density (Jc) of over MA cm-2 (77 K, 0 T) and a critical temperature of over 92 K. However, films prepared by spin coating shrink at lower spinning rates or have striation at higher spinning rates. Both shrunk films and films with striation have low Jc. Moreover, even if striation is not observed by scanning electron microscopy scale observation, a structure containing pores was confirmed by transmission electron microscopy. Such pores are considered to result in a low Jc of the films. To avoid such problems we adopted dip coating as the coating process in the TFA-MOD method. The dipped YBCO films have excellent Jc compared to the spun films. A typical dipped YBCO film of 0.25 µm in thickness on LaAlO3 single-crystalline substrate has a transport Jc of 5.3 MA cm-2 (77 K, 0 T).

Ethanol-based TFA–MOD method for preparation of YBCO films

“…Compared to standard TFA-MOD method results [2][3][4][5][6][7], the J C value for ethanol-based TFA-MOD YBCO film is relatively lower, possibly due to that the current processing parameters were mostly adopted from the methanol-based TFA-MOD method. Further investigation of optimizing the processing parameters for the ethanol-based TFA-MOD method is still undergoing.…”

“…Metal-organic deposition using trifluoroacetates (TFA-MOD) method is one of the most promising techniques for the fabrication of high quality YBa 2 Cu 3 O 7-x (YBCO) superconducting thin films [1][2][3][4][5][6][7]. Growth mechanism and influence of various processing parameters for TFA-MOD method have been widely investigated [8][9][10][11][12][13][14].…”

“…Methanol is the most commonly used solvent in TFA-MOD route [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. It is toxic and may cause death or blindness [15], which would involve serious health risk for industrial manufacture.…”

Calcining conditions for YBa/sub 2/Cu/sub 3/O/sub 7-x/ films by metalorganic deposition using trifluoroacetates

“…The biaxially textured Gd Zr O layer was produced by the ion-beamed-assisted-deposition [9]. A spinning rate of 4000 rpm and acceleration time of 0.4 s were used for coating of precursor films [10]. The precursor films were subsequently calcined in 4.2% humidified oxygen according to the calcining profile shown in Fig.…”

Optimization of Non-Fluorine Sol-Gel Derived YBCO Thin Films

“…The trifluoroacetate (TFA) precursor produces high quality films [2], however the corrosive toxic gas HF is produced as a by-product which may present problems in large scale manufacture. Alternatively, non-fluorine based precursors can produce high quality films as improvements in sol-gel techniques now allow atomic level mixing of cations [3].…”