Nuclear Techniques ›› 2016, Vol. 39 ›› Issue (10): 100202-100202.doi: 10.11889/j.0253-3219.2016.hjs.39.100202

• LOW ENERGY ACCELERATOR, RAY AND APPLICATIONS • Previous Articles     Next Articles

Influence of γ-ray irradiation on the point defect configurations and magnetic properties of MgO single crystals

CAO Mengxiong1, MA Yaru1, FAN Congli1, WANG Xingyu1, LIU Hao2, WANG Haiou3, ZHOU Weiping1, MA Chunlin1, TAN Weishi1   

  1. 1 Key Laboratory of Soft Chemistry and Functional Materials, Ministry of Education, Department of Applied Physics, Nanjing University of Science and Technology, Nanjing 210094, China;
    2 Suzhou Institute of Industrial and Technology, Suzhou 215104, China;
    3 Institute of Materials Physics, Hangzhou Dianzi University, Hangzhou 310018, China
  • Received:2016-08-12 Revised:2016-09-13 Online:2016-10-10 Published:2016-10-13
  • Supported by:

    Supported by National Natural Science Foundation of China (No.U1332106, No.11604067)

Abstract:

Background: d0 ferromagnetism challenges the understanding of magnetism in insulators. MgO, which is important for magnetic tunnel junctions, is an ideal material for investigating d0 ferromagnetism. The ferromagnetism in MgO has attracted great interests. Purpose: This study aims to investigate the influence of γ-ray irradiation on point defect configurations and magnetic properties of (100)-oriented MgO single crystals. Methods: The point defect configurations in irradiated-MgO single crystals were experimentally studied using synchrotron radiation diffuse scattering and ultraviolet-visible (UV-vis) absorption spectroscopy. Based on Huang's scattering theory, the isointensity profile of diffuse scattering was calculated by MATLAB program. The magnetic properties were measured by superconducting quantum interference device (SQUID). Results: ω-2θ scans and rocking curves of (200) and (311) peaks of samples indicated generation of point defects and lattice distortion in irradiated MgO single crystals. The presence of Frenkel defects in irradiated MgO single crystals was evidenced by reciprocal space mappings around the (200) reflection and UV-vis absorption spectra. The M-H and M-T curves of irradiated MgO single crystals remained the same as that of the unirradiated, demonstrating that the magnetic properties of irradiated MgO were unchanged. Conclusion: Lots of anion vacancies are generated by γ-ray irradiation in (100) MgO single crystals. However, the anion vacancies cannot induce d0 ferromagnetism in MgO single crystals.

Key words: ray irradiation, MgO single crystal, Point defect, Diffuse scattering, d0 ferromagnetism

CLC Number: 

  • TG115.22+3