Spin structure at zero magnetic field and field-induced spin reorientation transitions in a layered organic canted antiferromagnet bordering a superconducting phase
Spin structure at zero magnetic field and field-induced spin reorientation transitions in a layered organic canted antiferromagnet bordering a superconducting phase
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超导相边界的层状有机倾斜反铁磁体中零磁场下的自旋结构和场诱导的自旋重定向跃迁
DOI：
10.1103/physrevb.102.035102
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发表时间：
2020
影响因子：
3.7
通讯作者：
Tetsuaki Itou
中科院分区：
文献类型：
--
作者：
Kohsuke Oinuma;Naoki Okano;Hitoshi Tsunakawa;Shinji Michimura;Takuya Kobayashi;Hiromi Taniguchi;Kazuhiko Satoh;Julia Angel;Isao Watanabe;Yasuyuki Ishii;Hiroyuki Okamoto;Tetsuaki Itou
我们试图确定层状有机反铁磁体的自旋结构，（d8-BEDT-，其是在该族化合物中在环境压力下位于最接近Mott边界的关键材料，通过彻底研究其宏观磁化，由最近成功分配的同构材料的自旋结构激发，- （BEDT-[BEDT-TTF和d8-BEDT-TTF分别是双（亚乙基二硫代）四硫富瓦烯及其氘代分子]。我们测量了等温磁化强度后，仔细选择的测量温度和冷却速度在80 K左右，使反铁磁相的磁性可以有效地提取。因此，我们观察到的磁滞回线表示铁磁性和阶梯状行为时，施加平行于crystallographicandaxis磁场扫描，分别。根据自旋之间可能的相互作用，如交换相互作用和Dzyaloshinskiii-Moriya相互作用，讨论了与这些结果一致的可能的自旋结构。最后，我们断言-（d8-BEDT-）具有一个以易磁化轴为轴，净斜动量平行于轴的自旋结构，这与-（BEDT-）的自旋结构有着惊人的不同。我们认为，这种差异源于两种材料之间的层间相互作用的符号的不同。我们还阐明了这种材料在平行于三个主轴的磁场下的磁化过程的全貌，这也与-（BEDT-）的磁化过程相反。特别是，自旋反转转变，在一半的自旋旋转，是不是由轴磁场诱导，在-（BEDT-的情况下，但由轴磁场。最后，数值模拟和磁对称性分析，使我们能够确认的自旋结构的有效性提出的两个反铁磁体在零和高磁场。
We attempted to assign the spin structure of a layered organic antiferromagnet,-(d8-BEDT-, which is a key material located closest to the Mott boundary at ambient pressure among this family of compounds, by investigating its macroscopic magnetization thoroughly, motivated by a recent successful assignment of the spin structure of an isostructural material,-(BEDT-[BEDT-TTF and d8-BEDT-TTF are bis(ethylenedithio)tetrathiafulvalene and its deuterated molecule, respectively]. We measured the isothermal magnetization after careful choice of the measurement temperatures and cooling speed at around 80 K, so that the magnetism of the antiferromagnetic phase can be effectively extracted. Consequently, we observed hysteresis loops signifying ferromagnetism and steplike behavior when the magnetic field applied parallel to the crystallographicandaxes was swept, respectively. The possible spin structure consistent with these results was discussed in terms of probable interactions between the spins, such as exchange interactions and the Dzyaloshinskii-Moriya interaction. Eventually, we asserted that-(d8-BEDT-has a spin structure with the easy axis being theaxis and the net canted moment parallel to theaxis, which is surprisingly different from that of-(BEDT-. We suggested that this difference originates from the difference of the sign of the interlayer interaction between the two materials. We also elucidated the overall picture of the magnetization processes of this material under the magnetic fields parallel to the three principle axes, which are also in contrast to those of-(BEDT-. In particular, the spin-reverse transition at which half of the spins rotate bywas not induced by the-axis magnetic field, as in the case of-(BEDT-, but by the-axis magnetic field. Finally, numerical simulations and magnetic symmetry analysis enabled us to confirm the validity of the spin structures proposed for the two antiferromagnets under zero and high magnetic fields.