Helical magnetic ordering studied in single-crystalline GdBe13
Helical magnetic ordering studied in single-crystalline GdBe13
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单晶 GdBe13 的螺旋磁序研究
DOI：
10.1103/physrevb.102.174408
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发表时间：
2020
影响因子：
3.7
通讯作者：
Amitsuka Hiroshi
中科院分区：
文献类型：
--
作者：
Hidaka Hiroyuki;Mizuuchi Kota;Hayasaka Eikai;Yanagisawa Tatsuya;Ohara Jun;Amitsuka Hiroshi
通过对多晶样品的实验研究，发现具有型面心立方结构的绿柱石具有适当的螺旋磁有序性。在本研究中，我们进行了电阻率，比热，和磁化强度的测量单晶为了研究其螺旋有序的机制。这些测量结果表明，本化合物是一个金属系统，表现出磁有序的localmoments在= 24.8 K伴随着强磁波动延伸到温度远高于。此外，我们还绘制了[001]的磁场-温度（-）相图。在有序态下，在低场区由平行和垂直于螺旋面的磁结构组成的多畴态和在高场区可能的单畴锥形态组成。本文在假设一维层状晶体的基础上，利用海森堡交换相互作用的竞争，讨论了具有无公度序矢量q 0 =（0，0，0.285）的螺旋结构。通过平均场（MF）计算确定的交换相互作用的顺序变化可以基本上通过经由各向异性费米表面的Ruderman-Kittel-Kasuya-Yosida相互作用来理解，而磁矩的方向将由偶极-偶极相互作用确定。另一方面，MF理论预测的临界场比实验得到的小得多。为了讨论MF计算的偏差，我们给出了涨落诱导一级跃迁的可能性。
The beryllidewith the-type face-centered-cubic structure has been known to undergo a proper helical-magnet ordering from experimental studies using polycrystalline samples. In the present study, we carried out electrical resistivity, specific heat, and magnetization measurements of single-crystallinein order to investigate a mechanism of its helical ordering. These measurements reveal that the present compound is a metallic system exhibiting the magnetic ordering of localmoments at= 24.8 K accompanied with strong magnetic fluctuations extending to temperatures well above. Furthermore, we constructed a magnetic field–temperature (–) phase diagram for[001]. It consists of a multidomain state, which is composed of magnetic structures withapplied parallel and perpendicular to the helical plane, in the lower-magnetic-field region belowand a possible single-domain conical one in the higher-field region in the ordering state. The helical structure ofcharacterized by an incommensurate ordering vector q0 of (0, 0, 0.285) is discussed on the basis of a competition of Heisenberg exchange interactions between themoments assuming an one-dimensional layer crystal. The sequential change in the exchange interactions determined by a mean-field (MF) calculation can be essentially understood by the Ruderman-Kittel-Kasuya-Yosida interaction via anisotropic Fermi surfaces, whereas the orientation of the magnetic moments will be determined by the dipole-dipole interaction. On the other hand, the MF theory predicts a much smaller critical fieldthan the experimentally obtained one. To discuss the deviation offrom the MF calculation, we show a possibility of a fluctuation-induced first-order transition.