Magnetic properties of carbonado diamonds
Magnetic properties of carbonado diamonds
复制标题
黑金刚石的磁性
DOI：
10.1016/j.jmmm.2005.05.019
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发表时间：
2006
影响因子：
2.7
通讯作者：
J. Coey
中科院分区：
文献类型：
--
作者：
C. Fitzgerald;M. Venkatesan;A. Douvalis;J. Coey
黑金刚石是来源不明的多孔多晶金刚石，产于巴伊亚（巴西东北部）和中非共和国。它们兼具极高的硬度和韧性，是钻孔和切削工具的理想选择。包括铁、镍、铜和银在内的多种元素都与钻石伴生。根据锰掺杂金刚石可能本质上是铁磁性的建议，我们分析了来自巴西的六个样品，这些样品显示出高达 3Am2kg−1 的铁磁矩，该铁磁矩会因酸浸而降低。粉碎粉末的 X 射线衍射显示出立方金刚石结构，没有可见的第二相。扫描电子显微镜显示重金属分布不均匀，穆斯堡尔光谱表明铁以天然铁的形式存在。我们没有从黑金刚石中发现过渡金属掺杂铁磁碳存在的证据。黑金刚石的固有抗磁化率是−4.5×10−9m3kg−1，与金刚石的公认值−5×10−9m3kg−1 相似。
Carbonados are porous polycrystalline diamonds of uncertain origin, which are found at locations in Bahia (NE Brazil) and in the Central African Republic. Their combination of extreme hardness and toughness is ideal for drilling and cutting tools. A variety of elements including Fe, Ni, Cu and Ag are associated with the diamonds. Following a suggestion that Mn-doped diamond may be intrinsically ferromagnetic, we have analysed six samples from Brazil which show ferromagnetic moments of up to 3Am2kg−1, which is reduced by acid leaching. X-ray diffraction on the crushed powder showed a cubic diamond structure, with no secondary phases visible. Scanning electron microscopy shows an inhomogeneous distribution of heavy metals and Mössbauer spectroscopy indicates that iron is present as native iron. We find no evidence from the carbonados for the existence of transition-metal doped ferromagnetic carbon. The intrinsic diamagnetic susceptibility of carbonados is −4.5×10−9m3kg−1, similar to the accepted value for diamond,−5×10−9m3kg−1.