Vortex Pinning Properties at Grain Boundary in SmBa2Cu3 ${\text{O}}_{y}$ Superconducting Films With BaHfO3 Nanorods Controlled via Low-Temperature Growth

We investigated the effect of the BaHfO
₃
(BHO) nanorods' configuration on transport properties at artificial grain boundaries (GBs) in SmBa
₂
Cu
₃
O
_y
(SmBCO) superconducting films. To control the nanorods' configuration at the GBs, we deposited 3.0 vol.% BHO-doped SmBCO films on 5° [001]-tilt bicrystal (LaAlO
₃
)
_0.3
(SrAl
_0.5
Ta
_0.5
O
₃
)
_0.7
substrates at relatively low growth temperature of 750 °C via the pulsed laser deposition method adopting a seed layer technique. According to the transport results, the critical current density (J
_c
) at the GBs was improved in the films with the nanorods at low magnetic fields. In addition, field angular dependence of Jc was also improved for a wide range of field directions with a broad peak for B//c. We estimated that the BHO nanorods in the GBs pinned the Abrikosov-Josephson (AJ) vortices with various directions in the GBs. AJ vortex pinning can be controlled by configuration of a pinning center at GB.