Manjeshwar Anusha Kamath, Nair Sreejith, Rajapitamahuni Anil Kumar, James Richard D, Jalan Bharat
Department of Chemical Engineering and Materials Science, University of Minnesota-Twin Cities, Minneapolis, Minnesota 55455, United States.
Department of Aerospace Engineering and Mechanics, University of Minnesota-Twin Cities, Minneapolis, Minnesota 55455, United States.
ACS Nano. 2023 Nov 14;17(21):20999-21005. doi: 10.1021/acsnano.3c03625. Epub 2023 Sep 14.
Controlling defect densities in SrRuO films is the cornerstone for probing the intricate relationship among its structural, electrical, and magnetic properties. We combine film growth, electrical transport, and magnetometry to demonstrate the adsorption-controlled growth of phase-pure, epitaxial, and stoichiometric SrRuO films on SrTiO (001) substrates using solid source metal-organic molecular beam epitaxy. Across the growth window, we show that the anomalous Hall curves arise from two distinct magnetic domains. Domains with similar anomalous Hall polarities generate the stepped feature observed within the growth window, and those with opposite polarities produce the hump-like feature present exclusively in the highly Ru-poor film. We achieve a residual resistivity ratio (RRR = /) of 87 in a 50 nm-thick, coherently strained, and stoichiometric SrRuO film, the highest reported value to date on SrTiO (001) substrates. We hypothesize further improvements in the RRR through strain engineering to control the tetragonal-to-orthorhombic phase transformation and the domain structure of SrRuO films.
控制SrRuO薄膜中的缺陷密度是探究其结构、电学和磁学性质之间复杂关系的基石。我们结合薄膜生长、电输运和磁测量，以证明使用固体源金属有机分子束外延在SrTiO(001)衬底上通过吸附控制生长出相纯、外延且化学计量比的SrRuO薄膜。在整个生长窗口内，我们表明反常霍尔曲线源自两个不同的磁畴。具有相似反常霍尔极性的磁畴产生了在生长窗口内观察到的阶梯状特征，而具有相反极性的磁畴则产生了仅在高度贫Ru薄膜中出现的驼峰状特征。我们在一个50nm厚、相干应变且化学计量比的SrRuO薄膜中实现了87的剩余电阻率比（RRR = /），这是迄今为止在SrTiO(001)衬底上报道的最高值。我们推测通过应变工程进一步改善RRR，以控制SrRuO薄膜的四方相向正交相转变和畴结构。
