Carbon-doped MgB₂ polycrystalline bulk samples were prepared by reacting mixtures of Mg and B powders, with and without 0.5 wt.% of the amino acids glycine, alanine, valine, leucine or isoleucine. The amount of carbon introduced into the MgB₂ structure depends on the amino acid and is surprisingly higher for glycine, which has the lowest carbon content among the aliphatic amino acids. The critical temperatures of samples doped with all kinds of additives were lower than for the undoped sample. The critical current density was influenced by the additives to different extents, alanine, valine and leucine yielding the best results. The pinning force is also larger for these additives at T < 30 K. An analysis of the normalized flux pinning force behavior leads to the conclusion that point pinning is predominant in all samples.

通过使Mg和B粉末的混合物与0.5重量％的氨基酸甘氨酸，丙氨酸，缬氨酸，亮氨酸或异亮氨酸反应，来制备碳掺杂的MgB ₂多晶整体样品。引入到MgB ₂结构中的碳量取决于氨基酸，并且对于甘氨酸来说出乎意料地更高，甘氨酸在脂肪族氨基酸中具有最低的碳含量。掺杂各种添加剂的样品的临界温度低于未掺杂样品的临界温度。临界电流密度在不同程度上受到添加剂的影响，丙氨酸，缬氨酸和亮氨酸的效果最佳。这些添加剂在T时的钉扎力也较大 <30K。对归一化通量钉扎力行为的分析得出的结论是，在所有样本中钉扎都是主要的。