Analysis of Transport Properties of MOD YBCO Films With BaZrO3 as Artificial Vortex Pinning Centers

The transport properties of nanocomposite
$\text{YBa}_{2}\text{Cu}_{3}\text{O}_{7-x}$
(YBCO) films grown by metal–organic decomposition (MOD) and prepared with a low-fluorine-coating solution on SrTiO
₃
single-crystal substrates were studied with
$dc$
and microwave measurement techniques. As demonstrated in previous studies, the combination of these two techniques is a powerful tool for vortex pinning investigation. The BaZrO
₃
inclusions (BZO) as artificial pinning centers were introduced into the YBCO matrix by the excess of corresponding Ba and Zr precursor salts to the initial YBCO precursor solution up to 5 mol%. The effect of BZO was clearly observed in magnetic field dependence relations of critical current density
$(J_{c})$
and the complex surface impedance, i.e.,
$\mathit{\Delta}Z$
, at fixed temperature and magnetic field parallel to the
$c$
-axis. The result shows that BZO particles mainly act as isotropic pinning centers. The short-range vortex dynamics was probed by the ∼47.7-GHz microwave surface impedance technique. The derived vortex parameters
$r$
and
$k_{p}$
were sensitive to the presence of nanoparticles, indicating the effect of BZO on pinning. The joint field dependence relations of
$J_{c}$
and
$k_{p}$
help in elucidating the pinning regime in our nanocomposite MOD YBCO/BZO films.