Nanoscale disorder in high critical field, carbon-doped MgB2 hybrid physical-chemical vapor deposition thin films

作者：Zhu Y^*; Larbalestier D C; Voyles P M; Pogrebnyakov A V; Xi X X; Redwing J M

来源：Applied Physics Letters, 2007, 91(8): 082513.

DOI：10.1063/1.2775088

Carbon-doped MgB2 thin films deposited by hybrid physical-chemical vapor deposition (HPCVD) can have H-c2(0 K)similar to 70 T, anomalously high compared to bulk samples which have H-c2 about half this value. Using transmission electron microscopy, the authors show that the carbon content in HPCVD-grown Mg(B1-xCx)(2) grains is x <= 5%, and that most carbon forms an amorphous intergranular phase. The authors also find extensive structural disorder, including rotations about the c axis and small tilts of the c axis, with a domain size of 5-20 nm. The authors propose that strong electron scattering from the nanoscale disorder is responsible for the very high H-c2 in such films.

• 出版日期2007-8-20