Unexpected observation of splitting of skyrmion phase in Zn doped Cu2OSeO3.
Unexpected observation of splitting of skyrmion phase in Zn doped Cu2OSeO3.
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DOI：
10.1038/srep13579
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发表时间：
2015-09-09
影响因子：
4.6
通讯作者：
Yang HD
中科院分区：
文献类型：
--
作者：
Wu HC;Wei TY;Chandrasekhar KD;Chen TY;Berger H;Yang HD
采用固相反应合成了多晶 (Cu1−xZnx)2OSeO3 (0 ≤ x ≤ 0.2) 样品，并通过 X 射线衍射 (XRD) 进行了表征。 Zn 掺杂对饱和磁化强度 (MS) 的影响表明 Zn 有利于占据 Cu(II) 方锥晶位。在不同温度 (χ'ac-T) 和磁场强度 (χ'ac-H) 下测量交流磁化率 (χ'ac)。研究发现Zn掺杂浓度对M-T和χ′ac-T影响很大。斯格明子相是从 χ′ac-H 数据推断出来的，然后在不同 Zn 掺杂浓度的 H-T 相图中表示出来。引人注目且意想不到的观察结果是，斯格明子相区域随着 Zn 掺杂浓度的变化而分裂。有趣的是，从 dχ′ac/dH vs. H 曲线中还观察到伴随第二斯格明子相的第二圆锥形边界。化学掺杂产生的原子位点无序通过扭曲的 Cu(II) 方锥体的 Dzyaloshinskii-Moriya (DM) 矢量的变化来调节微妙的磁相互作用，从而可能发生斯格明子相的分裂。这些发现说明了使用化学和原子修饰来调节 Cu2OSeO3 斯格明子相的温度和场依赖性的潜力。
Polycrystalline (Cu1−xZnx)2OSeO3 (0 ≤ x ≤ 0.2) samples were synthesized using solid-state reaction and characterized by X-ray diffraction (XRD). The effect of Zn doping upon saturation magnetization (MS) indicates that the Zn favors to occupying Cu(II) square pyramidal crystallographic site. The AC susceptibility (χ′ac) was measured at various temperatures (χ′ac–T) and magnetic field strengths (χ′ac–H). The Zn doping concentration is found to affect greatly the M-T and χ′ac-T. The skyrmion phase has been inferred from the χ′ac-H data, and then indicated within the H-T phase diagrams for various Zn doping concentrations. The striking and unexpected observation is that the skyrmion phase region becomes split upon Zn doping concentration. Interestingly, second conical boundary accompanied by second skyrmion phase was also observed from dχ′ac/dH vs. H curves. Atomic site disorder created by the chemical doping modulates the delicate magnetic interactions via change in the Dzyaloshinskii-Moriya (DM) vector of distorted Cu(II) square pyramidal, thereby splitting of skyrmion phase might occur. These findings illustrate the potential of using chemical and atomic modification for tuning the temperature and field dependence of skyrmion phase of Cu2OSeO3.