Magnetic Field of BG-VG Transition Depending on the Nanorods Shape in $\hbox{BaHfO}_{3}$-Doped $\hbox{SmBa}_{2}\hbox{Cu}_{3}\hbox{O}_{y}$ Films

The vortex state under the magnetic held around vortex glass (VG)-Bose glass (BG) transition held was investigated in the SmBa
₂
Cu
₃
O
_y
(SmBCO) films with BaHfO
₃
(BHO) nanorods. We prepared two films with different forms of the nanorods (thick-straight and thin-tilted), and we used the magnetic held angular dependence of flux flow resistivity (p - θ) to identify a vortex state. From a comparison between the p - θ curves in completely BG and VG phases, it was revealed that the existence of deep and sharp dip structure along the c-axis direction of the SmBCO matrix (B//c) was an evidence of the BG state in both the films. In the magnetic held region around VG-BG transition, shallower and broader dips than the dips in the BG state were observed at B//c in both the films. In addition, the dips became deeper with increase of the magnetic held in this region in each film. Therefore, we considered the vortex state of both the films was an intermediate and/or a transient state of BG and VG. Under all magnetic fields, the film with thick and straight BHO nanorods showed stronger c-axis correlated flux pinning force than the film with thin and tilted nanorods. We suggested the intermediate state of the hlm with thicker and straighter nanorods was similar to the BG state compared with another hlm from the both of experimental results and reported theory.