ANTIFERROMAGNETISM IN GAMMA-PHASE MN-IR ALLOYS
ANTIFERROMAGNETISM IN GAMMA-PHASE MN-IR ALLOYS
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DOI：
10.1143/jpsj.36.445
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发表时间：
1974-01-01
影响因子：
1.7
通讯作者：
YAMAOKA, T
中科院分区：
文献类型：
--
作者：
YAMAOKA, T
研究了无序γ相Mn1-xIrx(0.05<x<0.35)合金的晶体学和磁性能。在富锰合金中，轴比 c/a>1 的四方变形发生在低于其尼尔温度 TN 的温度下。反铁磁有序态的四方变形温度Tdin随着Ir的增加而迅速降低，并且x>0.15的合金在低温下仍保持立方体。另一方面，TN 随着 Ir 合金化而增加，其速率约为 9 K/at%Ir，直至 730 K atx=0.25，对于 fcc Mn，外推至 500±20 K。结论是，TN的异常升高主要不是由于原子有序性，也不是晶格膨胀导致的交换相互作用的增强，而是合金化引起的能带结构的扰动导致了更强的磁相互作用。发现 x=0.25 附近的 Cu3Au 型原子排序可将 TN 提高约 200 K。讨论了四方畸变的起源。
Crystallographic and magnetic properties were studied in the disordered γ-phase Mn1-xIrx(0.05<x<0.35) alloys. In Mn rich alloys, tetragonal distortion with axial ratioc/a>1 occurs at a temperature below their Néel temperature,TN. The tetragonal distortion temperature,Tdin the antiferromagnetic ordered state decreases rapidly with increasing Ir and the alloys withx>0.15 remain cubic down to low temperatures. On the other hand,TNincreases with alloying Ir at a rate of about 9 K/at%Ir up to 730 K atx=0.25 and it is extrapolated to 500±20 K for fcc Mn. It was concluded that the anomalous rise ofTNis not mainly attributed to atomic order nor to the enhancement of exchange interaction due to lattice expansion, but that the perturbation of band structure due to alloying leads to stronger magnetic interaction. A Cu3Au type atomic ordering in the vicinity ofx=0.25 was found to raise theTNby about 200 K. The origin of tetragonal distortion is discussed.