Enhanced Pinning in a Broad Angular Range by 1D-APCs With a Coherent Interface

One-dimensional artificial pinning centers (1D-APCs) in YBa
₂
Cu
₃
O
_7-x
nanocomposite films provide strong collective pinning at magnetic field
B
//
c
-axis. In this work, we reveal a 1D-APC/YBa
₂
Cu
₃
O
_7-x
interface is preferred for high pinning efficiency of individual 1D-APCs including BaHfO
₃
and BaZrO
₃
. The coherent 1D-APC/YBa
₂
Cu
₃
O
_7-x
interface may be obtained via either growth of the nanocomposite films at optimal condition or Ca-diffusion to dynamically reduce the interface strain during the nanocomposite film growth. Interestingly, the high pinning efficiency of the 1D-APCs with coherent interfaces with YBCO not only lead to a high critical current density (
J
_c
) in magnetic fields up to 9.0 T at
H
//
c
-axis but also enhanced
J
_c
over a larger angular range when
H
is away from
H
//
c
-axis up to θ = 60–80 degree than that in the case the interface is defective. This result suggests the importance of understanding and engineering the APC/YBCO interface for optimal pinning in nanocomposite films.