Two-dimensional electron gases at oxide surfaces or interfaces show exotic ordered states of matter, like superconductivity, magnetism or spin-polarized states, and are a promising platform for alternative oxide-based electronics. Here we directly image a dense population of randomly distributed ferromagnetic domains of ∼40 nm typical sizes at room temperature at the oxygen-deficient surface of SrTiO3, a non-magnetic transparent insulator in the bulk. We use laser-based photoemission electron microscopy, an experimental technique that gives selective spin detection of the surface carriers, even in bulk insulators, with a high spatial resolution of 2.6 nm. We furthermore find that the Curie temperature in this system is as high as 900 K. These findings open perspectives for applications in nano-domain magnetism and spintronics using oxide-based devices, for instance through the nano-engineering of oxygen vacancies at surfaces or interfaces of transition-metal oxides.

中文翻译：

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非磁性氧化物表面的室温铁磁纳米域的成像。

氧化物表面或界面处的二维电子气显示出奇特有序的物质状态，例如超导性，磁性或自旋极化状态，并且是基于氧化物的电子学的有前途的平台。在这里，我们直接在室温下，在主体中的非磁性透明绝缘体SrTiO3的缺氧表面上，形成密集的随机分布的铁磁畴，其典型尺寸约为40 nm。我们使用基于激光的光发射电子显微镜，一种实验技术，即使在绝缘体中，也可以选择性旋转检测表面载流子，具有2.6 nm的高空间分辨率。我们还发现，该系统中的居里温度高达900K。