Effect of ${\rm BaZrO}_{3}$ Addition and Film Growth on Superconducting Properties of $({\rm Nd},{\rm Eu},{\rm Gd}){\rm Ba}_{2}{\rm Cu}_{3}{\rm O}_{y}$ Thin Films

We report that (Nd,Eu,Gd)Ba
₂
Cu
₃
O
_y
(NEG) films grown by low temperature growth (LTG) technique exhibit excellent superconducting properties in magnetic fields. In this study, we aim to improve the superconducting properties of NEG films by means of a modified LTG technique (mLTG) in which the surface of a highly
c
-axis oriented NEG seed layer is decorated by BaZrO
₃
(BZO) nanodots and an NEG upper layer on the seed layer is deposited at relatively low substrate temperature by using a BZO doped NEG123 target. From magnetic field and angular dependence of
J

_c
, even
J

_c
peak around
B
//
c
-axis of an LTG-NEG films including BZO was larger than that of LTG-NEG without BZO. Furthermore, the mLTG-NEG films showed larger
J

_c
peak than the LTG-NEG films with BZO and the
J

_c
peak increased with increasing the BZO nanodots density. TEM images clarified that these films included BZO nanorods with a diameter of 5 ~ 10 nm and the number density increased by introducing the BZO nanodots. Therefore, we concluded that the mLTG enabled to improve the superconducting properties due to control the configuration of BZO nanorods in the films.