Abstract

A correlation was found between the endset temperature of the superconducting transition T(R = 0) of YBa₂Cu₃O_7 – x films 100–200 nm thick, obtained by pulsed laser deposition on SrTiO₃(100) substrates with a temperature of ~740°C, and the regimes of high-speed filtering of the erosion plume formed upon ablation of the material the target. Under deposition conditions, we changed the width of the filtering window, the repetition rate of the atomized material passing through the filter onto the substrate, and the radiation energy density of the KrF excimer laser on the target surface. At deposition rates of less than 0.1 nm s^–1, the values of T(R = 0) did not exceed 77 K, and pyramids were formed on the surface of the films up to 80 nm in height along the c axis in the form of spirals with rectangular bases and steps of 1–2 nm along the lateral faces. With an increase in the deposition rate from 0.1 to 0.6 nm s^–1, T(R = 0) increased to 86 K. These regimes corresponded to a wavy pyramid surface up to 40 nm in height with rounded bases up to 1500 nm in diameter and irregular steps 1–4 nm on the side slopes. Faceted crystals with a width from 20–30 to 500 nm in the base grew along the boundaries between the pyramids during the deposition. This morphology of the growth surface was explained by the high flow rate of the sputtered material, which is determined by the frequency filtering of the erosion plume and the energy density in the pulse upon predominantly surface diffusion.

中文翻译：

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脉冲激光沉积获得的YBa 2 Cu 3 O 7-x薄膜的表面形貌与超导转变的终止温度之间的关系

摘要

发现在100-200 nm厚的YBa ₂ Cu ₃ O _{7 – x}薄膜的超导转变温度T（R = 0）的极限温度之间具有相关性，该薄膜是通过在SrTiO ₃（100）衬底上以脉冲温度沉积的方式进行脉冲激光沉积而获得的。约740°C的温度，并且在烧蚀靶材时形成了高速过滤腐蚀羽流的状态。在沉积条件下，我们更改了滤镜窗口的宽度，雾化材料通过滤镜到达基板上的重复率以及目标表面上KrF准分子激光的辐射能量密度。在小于0.1 nm s ^–1的沉积速率下， T（R = 0）不超过77 K，并且在沿c轴高至80 nm的薄膜表面上形成金字塔，呈螺旋状，带有矩形底面，沿侧面的距离为1-2 nm。面孔。随着沉积速率从0.1 nm s ^–1增加到0.6 nm ，T（R= 0）增加到86K。这些状态对应于高度不超过40 nm的波状金字塔表面，且圆形底边的直径不超过1500 nm，边坡的不规则台阶为1-4 nm。在沉积过程中，基部宽度为20–30至500 nm的多面晶体沿着金字塔之间的边界生长。生长表面的这种形态可以通过溅射材料的高流速来解释，这是由腐蚀羽流的频率过滤和主要在表面扩散时脉冲中的能量密度决定的。