Nature Communications ( IF 14.7 ) Pub Date : 2022-09-06 , DOI: 10.1038/s41467-022-33017-1
Ruiqing Cheng 1 , Lei Yin 1 , Yao Wen 1 , Baoxing Zhai 1 , Yuzheng Guo 2 , Zhaofu Zhang 3 , Weitu Liao 1 , Wenqi Xiong 1 , Hao Wang 1 , Shengjun Yuan 1 , Jian Jiang 1 , Chuansheng Liu 1 , Jun He 1, 4
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The discovery of magnetism in ultrathin crystals opens up opportunities to explore new physics and to develop next-generation spintronic devices. Nevertheless, two-dimensional magnetic semiconductors with Curie temperatures higher than room temperature have rarely been reported. Ferrites with strongly correlated d-orbital electrons may be alternative candidates offering two-dimensional high-temperature magnetic ordering. This prospect is, however, hindered by their inherent three-dimensional bonded nature. Here, we develop a confined-van der Waals epitaxial approach to synthesizing air-stable semiconducting cobalt ferrite nanosheets with thickness down to one unit cell using a facile chemical vapor deposition process. The hard magnetic behavior and magnetic domain evolution are demonstrated by means of vibrating sample magnetometry, magnetic force microscopy and magneto-optical Kerr effect measurements, which shows high Curie temperature above 390 K and strong dimensionality effect. The addition of room-temperature magnetic semiconductors to two-dimensional material family provides possibilities for numerous novel applications in computing, sensing and information storage.
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用于室温二维磁性半导体的超薄铁氧体纳米片
超薄晶体磁性的发现为探索新物理学和开发下一代自旋电子器件提供了机会。然而,居里温度高于室温的二维磁性半导体却鲜有报道。具有强相关d轨道电子的铁氧体可能是提供二维高温磁排序的替代候选者。然而,这种前景受到其固有的三维键合性质的阻碍。在这里,我们开发了一种受限范德华外延方法,使用简便的化学气相沉积工艺合成厚度小至一个晶胞的空气稳定半导体钴铁氧体纳米片。通过振动样品磁力测量、磁力显微镜和磁光克尔效应测量证明了硬磁行为和磁畴演化,显示出390 K以上的高居里温度和强维数效应。将室温磁性半导体添加到二维材料系列中,为计算、传感和信息存储领域的众多新颖应用提供了可能性。