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叶润, 叶邦角. 正电子湮没谱学研究氧离子注入AlN薄膜中缺陷对磁性影响[J]. 原子核物理评论, 2024, 41(1): 498-503. DOI: 10.11804/NuclPhysRev.41.2023CNPC66
引用本文: 叶润, 叶邦角. 正电子湮没谱学研究氧离子注入AlN薄膜中缺陷对磁性影响[J]. 原子核物理评论, 2024, 41(1): 498-503. DOI: 10.11804/NuclPhysRev.41.2023CNPC66
Run YE, Bangjiao YE. Effect of Defects on Magnetic Properties of O+-implanted AlN Films by Positron Annihilation Spectroscopy[J]. Nuclear Physics Review, 2024, 41(1): 498-503. DOI: 10.11804/NuclPhysRev.41.2023CNPC66
Citation: Run YE, Bangjiao YE. Effect of Defects on Magnetic Properties of O+-implanted AlN Films by Positron Annihilation Spectroscopy[J]. Nuclear Physics Review, 2024, 41(1): 498-503. DOI: 10.11804/NuclPhysRev.41.2023CNPC66

正电子湮没谱学研究氧离子注入AlN薄膜中缺陷对磁性影响

Effect of Defects on Magnetic Properties of O+-implanted AlN Films by Positron Annihilation Spectroscopy

  • 摘要: 在氧离子注入的AlN薄膜AlN: \rmO_5\times10^16(剂量为5\times10^16 cm−2)和AlN: \rmO_2\times10^17(剂量为2\times10^17 cm−2)中观察到了室温铁磁性。所观察到的磁各向异性表明,氧离子注入的AlN薄膜中铁磁性是本征特性。在垂直于样品平面的外加磁场下,AlN: \rmO_5\times10^16中的饱和磁化强度约为0.68 emu/g,高于 AlN: \rmO_2\times10^17中的饱和磁化强度0.09 emu/g。这是由于过高的氧离子剂量使得更多的氧离子占据相邻的Al离子位置,导致了反铁磁耦合的出现。正电子湮没多普勒展宽谱表明在氧离子注入的AlN薄膜中存在大量的Al空位。第一性原理计算表明氧离子注入的AlN薄膜中的铁磁性主要来源于Al空位,而高浓度的Al空位形成双空位或空位团将会使得AlN样品从铁磁性到反铁磁性转变,最终使样品的铁磁性减弱。

     

    Abstract: Room-temperature ferromagnetism is observed in the O+-implanted AlN films with O+ doses of 5\times10^16 cm−2 (AlN: \rmO_5\times10^16 ) and 2\times10^17 cm−2 (AlN: \rmO_2\times10^17 ). The observed magnetic anisotropy indicates that the ferromagnetism is attributed to the intrinsic properties of O+-implanted AlN films. The out-of-plane saturation magnetization (M_\rmS) of the AlN: \rmO_5\times10^16 is about 0.68 emu/g, much higher than that of AlN: \rmO_2\times10^17 , 0.09 emu/g, which is due to the excessively high O+ dose made more O+ ions occupy adjacent Al3+ positions in forms of antiferromagnetic coupling. Doppler broadening of positron annihilation radiation measurements demonstrate the existence of Al vacancies in the O+-implanted AlN films. The first-principles calculations suggest that the ferromagnetism originates mainly from the Al vacancies. Meanwhile, the formation of divacancies or vacancy clusters by high concentrations of Al vacancies will lead to the transformation of VAl–VAl coupling from ferromagnetim to antiferromagnetism, ultimately weakening the ferromagnetism of the sample.

     

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