(Cu,C)Ba2Ca3Cu4O
y
((Cu,C)-1234) is a nontoxic, non-rare-earth-element-included
superconducting material characterized by high critical temperature T
C, critical current density J
C, and irreversible field μ0
H
irr. The growth of superconducting (Cu,C)-1234 thin films
by using the pulsed laser deposition (PLD) method circumvents the
challenges associated with high-pressure bulk crystal growth. Nonetheless,
several critical aspects regarding the growth mechanism, strain effects,
and thickness-dependent behavior in PLD-grown (Cu,C)-1234 thin films
remain poorly understood. Here, the thickness dependence of the superconducting
properties in (Cu,C)-1234 thin films is reported systematically. Highly
oriented, a-axis (Cu,C)-1234 films on LaAlO3 (LAO) (1 0 0) substrates, with thickness ranging from 25 to 500
nm, is realized. Transport measurements reveal that films with a critical
thickness of ∼250 nm exhibit optimized superconducting performance,
as characterized by uniform surface morphology, high critical temperature,
strong pining energy, and large irreversible field. Moreover, films
near this optimal thickness display an increase in the irreversible
field μ0
H
irr, approximately
9 T at 49 K (0.77T
C), which could be attributed
to an elevated effective pinning barrier. This result paves the way
for the application of the (Cu,C)-1234 thin film under high magnetic
fields.