Enhanced ferromagnetic transition temperature induced by a microscopic structural rearrangement in the diluted magnetic semiconductor Ge_1-xMn_xTe
Enhanced ferromagnetic transition temperature induced by a microscopic structural rearrangement in the diluted magnetic semiconductor Ge_1-xMn_xTe
复制标题
稀磁半导体 Ge_1-xMn_xTe 中微观结构重排引起的铁磁转变温度增强
DOI：
10.1103/physrevb.95.224418
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发表时间：
2017
影响因子：
3.7
通讯作者：
and Y. Taguchi
中科院分区：
文献类型：
--
作者：
M. Kriener;T. Nakajima;Y. Kaneko;A. Kikkawa;D. Hashizume;K. Kato;M. Takata;T. Arima;Y. Tokura;and Y. Taguchi
通过X射线衍射和磁化强度与锰浓度的函数关系研究了稀磁半导体的磁性与微观结构方面之间的相关性。在缓慢冷却的菱面体畸变相中出现高的铁磁转变温度与强畸变贫锰区和弱畸变富锰区的形成和共存直接相关。结果表明，弱畸变相分数是导致高转变温度的原因。当Mn浓度变大时，富Mn区开始转变为无畸变的立方结构，同时转变温度被抑制。通过确定合适的退火条件，我们成功地提高了转变温度到200 K以上的锰浓度接近立方相。结构数据表明，弱扭曲的相分数可以恢复在立方区域的代价后，增强的转变温度，清楚地建立高的转变温度和弱扭曲的富锰相分数之间的直接联系。
The correlation between magnetic properties and microscopic structural aspects in the diluted magnetic semiconductoris investigated by x-ray diffraction and magnetization as a function of the Mn concentration. The occurrence of high ferromagnetic-transition temperatures in the rhombohedrally distorted phase of slowly cooledis shown to be directly correlated with the formation and coexistence of strongly distorted Mn-poor and weakly distorted Mn-rich regions. It is demonstrated that the weakly distorted phase fraction is responsible for the occurrence of high-transition temperatures in. When the Mn concentration becomes larger, the Mn-rich regions start to switch into the undistorted cubic structure, and the transition temperature is suppressed concurrently. By identifying suitable annealing conditions, we successfully increased the transition temperature to above 200 K for Mn concentrations close to the cubic phase. Structural data indicate that the weakly distorted phase fraction can be restored at the expense of the cubic regions upon the enhancement of the transition temperature, clearly establishing the direct link between high-transition temperatures and the weakly distorted Mn-rich phase fraction.