Spin-Spin Correlation Length in MnSi Thin Films
Spin-Spin Correlation Length in MnSi Thin Films
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DOI：
10.1143/jpsj.81.124709
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发表时间：
2012-12-01
影响因子：
1.7
通讯作者：
Suellow, Stefan
中科院分区：
文献类型：
--
作者：
Engelke, Josefin;Reimann, Tommy;Suellow, Stefan
利用分子束外延技术，在Si(111)衬底上同时蒸发Mn和Si，制备了MnSi薄膜。RHEED分析和透射电子显微镜研究相结合的结果表明，这种共沉积技术可以得到光滑的薄膜。电阻率测量显示出与块体MnSi性质相同的金属行为。由电阻率数据和SQUID磁强计测得的磁有序温度T为43K，与体积值相比有很大提高。然而，对于最薄的薄膜，观察到T级的减少，这是由于薄膜表面附近的自旋-自旋相互作用的减少所解释的。最近，有人指出，自旋-自旋关联长度比其他巡回磁性材料的已知长度要大得多。相反，我们发现耦合范围可以估计为7个单分子层，并且不超过普通磁体的值。
Thin MnSi films have been prepared on Si(111) by molecular beam epitaxy under simultaneous evaporation of Mn and Si. RHEED analysis in combination with TEM investigation reveals that this codeposition technique leads to smooth films. Resistivity measurements show a metallic behavior that is qualitatively the same as for bulk MnSi. The magnetic ordering temperature T-ord of 43 K, which has been determined from resistivity data and by SQUID magnetometry, is considerably enhanced compared to the bulk value. For the thinnest films, however, a decrease of T-ord is observed which is explained by the reduction of the spin-spin interaction near the surfaces of the film. Recently, it has been stated, that the spin-spin correlation length is much larger than known from other itinerant magnetic materials. In contrast, we show that the coupling range can be estimated as 7 monolayers and does not exceed the values of common magnets.