Vacancy-induced ferromagnetism in ZnO probed by spin-polarized positron annihilation spectroscopy
Vacancy-induced ferromagnetism in ZnO probed by spin-polarized positron annihilation spectroscopy
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DOI：
10.1063/1.4979696
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发表时间：
2017-04
影响因子：
4
通讯作者：
M. Maekawa;H. Abe;A. Miyashita;S. Sakai;S. Yamamoto;A. Kawasuso
中科院分区：
文献类型：
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作者：
M. Maekawa;H. Abe;A. Miyashita;S. Sakai;S. Yamamoto;A. Kawasuso
我们通过结合使用自旋极化正电子湮没谱和磁化测量，研究了氧注入诱导的ZnO铁磁性。磁化测量表明，氧注入后出现铁磁性，并且在高于573 K的温度下进行注入后退火时铁磁性消失。湮没辐射的多普勒展宽（DBAR）谱显示，氧注入后在磁场反转时出现不对称性。考虑锌空位的理论计算很好地解释了正负磁场之间获得的差分DBAR谱。退火导致DBAR谱磁场反转不对称性的消失与磁化测量中对铁磁性的观察结果一致。这些结果表明，辐射诱导的锌空位是所观察到的ZnO铁磁性的来源。
We investigated the ferromagnetism of ZnO induced by oxygen implantation by using spin-polarized positron annihilation spectroscopy together with magnetization measurements. The magnetization measurements showed the appearance of ferromagnetism after oxygen implantation and its disappearance during post-implantation annealing at temperatures above 573 K. The Doppler broadening of annihilation radiation (DBAR) spectrum showed asymmetry upon field reversal after oxygen implantation. The obtained differential DBAR spectrum between positive and negative magnetic fields was well-explained with a theoretical calculation considering zinc vacancies. The disappearance of the field-reversal asymmetry of the DBAR spectrum as a result of annealing agreed with the observations of ferromagnetism by magnetization measurements. These results suggest the radiation-induced zinc vacancies to be the source of the observed ferromagnetism of ZnO.