Nature of magnetism in Co- and Mn-doped ZnO prepared by sol-gel technique
Nature of magnetism in Co- and Mn-doped ZnO prepared by sol-gel technique
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DOI：
10.1063/1.2166598
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发表时间：
2006-04
影响因子：
3.2
通讯作者：
A. Manivannan;P. Dutta;G. Glaspell;M. Seehra
中科院分区：
文献类型：
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作者：
A. Manivannan;P. Dutta;G. Glaspell;M. Seehra
报道了Co0.05Zn0.95O和Mn0.05Zn0.95O块体样品在5%H2/95%Ar气氛中573K热处理6h前后的磁学性质，所得样品的磁化率χ符合居里-魏斯定律：χ=χ0+C/(T−θ)。C的大小与Co2+和Mn2+态的预期磁矩一致。氢化后的样品具有室温铁磁性，其磁矩为0.35μB/Co位，磁滞回线为Hc≃600Oe，剩磁为0.45emu/g，饱和磁化强度为ms≃1.2emu/g。在氢化条件下，Co/ZnO和Mn/ZnO的这一差异表明，n型掺杂导致了在Co/ZnO中RTFM的稳定，而在Mn/ZnO中则没有，后者可能需要p-T型掺杂。
Magnetic properties of sol-gel-prepared bulk samples of Co0.05Zn0.95O and Mn0.05Zn0.95O are reported before and after annealing in 5%H2∕95%Ar at 573 K for 6 h. The as-prepared samples are paramagnetic with the magnetic susceptibility χ following the Curie-Weiss law: χ=χ0+C∕(T−θ). The magnitudes of C are consistent with the magnetic moments expected for the Co2+ and Mn2+ states. After hydrogenation, the magnetism of Mn∕ZnO is unchanged but Co∕ZnO acquires room-temperature ferromagnetism (RTFM) with a magnetic moment of 0.35μB∕Co site and hysteresis loop with coercivity Hc≃600Oe, remanence Mr≃0.45emu∕g, and saturation magnetization Ms≃1.2emu∕g. Electron magnetic-resonance spectroscopy at 9.28 GHz gives signals corresponding to the Co2+ and Mn2+ states for the paramagnetic states and a broad FM signal for the hydrogenated Co∕ZnO. This difference under hydrogenation between Co∕ZnO and Mn∕ZnO suggests that n-type doping leads to stabilizing of RTFM in Co∕ZnO but not in Mn∕ZnO, the latter perhaps requiring p-ty...