准二维CoTa 2 O 6的热氨解反应得到了O2-/N3-和阴离子空位有序的Co2+ Ta 5 + 2 O 6-xN 2x/3 $\Box$ x/3(x $\leq$ 0.15),其表现出从反铁磁性到室温铁磁性以上的缺陷设计的转变,这一点通过衍射、光谱和磁性表征得到了证实。第一性原理计算揭示了铁磁性的起源是一种特殊的CoON组态,N位于Wyckoff位置8 j,打破了ab平面的镜像对称性。压力诱导的电子相变也被预测在24.5 GPa左右,伴随着绝缘体到金属的转变和磁矩消失。
英文摘要:
Thermal ammonolysis of quasi-two-dimensional (quasi-2D) CoTa2O6 yields the O2-/N3- and anionic vacancy ordered Co2+Ta5+2O6-xN2x/3$\Box$x/3 (x $\leq$ 0.15) that exhibits a transition from antiferromagnetism to defect engineered above room-temperature ferromagnetism as evidenced by diffraction, spectroscopic and magnetic characterizations. First-principles calculations reveal the origin of ferromagnetism is a particular CoON configuration with N located at Wyckoff position 8j, which breaks mirror symmetry about ab plane. A pressure-induced electronic phase transition is also predicted at around 24.5 GPa, accompanied by insulator-to-metal transition and magnetic moment vanishing.
Synergetic effect of edge states and point defects to tune ferromagnetism in CVD-grown vertical nanostructured MoS2: A correlation between electronic structure and theoretical study
Inducing ferromagnetism by structural engineering in a strongly spin-orbit coupled oxide
Universität Würzburg(维尔茨堡大学);International Research Centre MagTop, Institute of Physics, Polish Academy of Sciences(波兰科学院物理研究所磁顶国际研究中心);CNR-SPIN, UOS Salerno(萨莱诺国家研究委员会自旋单元);Leibniz Institute for Solid State and Materials Research Dresden(德累斯顿莱布尼兹固体与材料研究所);TU Dresden(德累斯顿工业大学);Synchrotron SOLEIL(索雷尔同步辐射中心)
Engineering room-temperature multiferroicity in Bi and Fe codoped BaTiO3
Fe掺杂到BaTiO 3中,稳定了顺电六方相,代替了铁电四氢呋喃[P. P. et al. Phys. Rev. B,101,064409(2020)]。我们发现,同时掺杂的Bi和Fe到钛酸钡有效地提高了磁电(ME)多铁性响应(铁磁性和铁电性)在室温下,通过仔细调整的Fe价态,随着控制恢复的铁电性,四相。随着Bi掺杂量的增加,Ba_(1-x)Bi_xTi_(0.9)Fe_(0.1)O_3(0<x<0.1)样品的介电常数随温度的变化逐渐增大,介电损耗角正切值逐渐减小,这使得Bi-Fe共掺杂量较高的样品(x=0.08)有望用作室温高k介电材料。有趣的是,x=0.08(Bi-Fe共掺杂)样品不仅被发现在室温下比x=0(仅掺杂Fe)强铁电性(~20倍)和铁磁性(~6倍),而且还观察到更好的绝缘性(更大的带隙),具有更大的ME耦合的间接特征,如从磁矫顽场随着温度降低的异常减少所指示的。因此,室温ME多铁性已被设计在Bi和Fe共掺杂的BTO(钛酸钡)化合物。
Dominant in-plane anomalous Hall effect in a monoclinic room-temperature ferromagnet
California Institute of Technology(加州理工学院);University of Rochester(罗切斯特大学);University of Tokyo(东京大学);High Energy Accelerator Research Organization(高能加速器研究机构);RIKEN Center for Emergent Matter Science(理化学研究所新兴物质科学中心)