We have systematically studied the magnetic properties of Cu$_{4-x}$Zn$_x$(OH)$_6$FBr by the neutron diffraction and muon spin rotation and relaxation ($μ$SR) techniques. Neutron-diffraction measurements suggest that the long-range magnetic order and the orthorhombic nuclear structure in the $x$ = 0 sample can persist up to $x$ = 0.23 and 0.43, respectively. The temperature dependence of the zero-field (ZF) $μ$SR spectra provide two characteristic temperatures, $T_{A0}$ and $T_λ$. Comparison between $T_{A0}$ and $T_M$ from previously reported magnetic-susceptibility measurements suggest that the former comes from the short-range interlayer-spin clusters that persist up to $x$ = 0.82. On the other hand, the doping level where $T_λ$ becomes zero is about 0.66, which is much higher than threshold of the long-range order, i.e., $\sim$ 0.4. Our results suggest that the change in the nuclear structure may alter the spin dynamics of the kagome layers and a gapped quantum-spin-liquid state may exist above $x$ = 0.66 with the perfect kagome planes.
Direct observation of the ground state of a 1/3 quantum magnetization plateau in SrMn$_3$P$_4$O$_{14}$ using neutron diffraction measurements
利用中子衍射测量可以直接研究磁化平台场的基态(平台基态)。我们对自旋为5/2的三聚体物质SrMn $_3$ P $_4$ O $_{14}$在磁化平台场中进行了中子衍射测量。用孤立三聚体模型的平台基态中每个自旋的期望值计算的磁反射积分强度与在磁化平台场中的实验结果吻合得很好。我们成功地在SrMn $_3$ P $_4$ O $_{14}$中直接观察到了一个平台基态。
Possible stripe phases in the multiple magnetization plateaus in TbB$_4$ derived from single-crystal neutron diffraction under pulsed high magnetic fields
Magnetic Order of Dresselhaus-type Antiferromagnet EuIr$_4$In$_2$Ge$_4$ Studied by Single Crystal Neutron Diffraction
Materials Sciences Research Center, Japan Atomic Energy Agency(日本原子力研究机构材料科学研究中心);Advanced Science Research Center, Japan Atomic Energy Agency(日本原子力研究机构先进科学研究中心);J-PARC center, Japan Atomic Energy Agency(日本原子力研究机构J-帕克中心);Comprehensive Research Organization for Science and Society(综合科学研究机构);Department of Physics, Tokyo Metropolitan University(东京都立大学物理系);RIKEN Center for Emergent Matter Science(理化学研究所新兴物质科学中心)
Neutron-diffraction and linear {Grüneisen} parameter studies of magnetism in NdFe$_2$Ga$_8$
我们通过中子衍射和温度调制线性{Grüneisen}参数测量来研究NdFe $_2$ Ga $_8$的磁性。以前的实验测量表明,在10和14.5 K,分别有两个磁转变。中子衍射测量证实,较低的是一个反铁磁(AFM)过渡与相称的磁结构。公度和非公度(IC)的磁峰被发现低于较高的过渡,但它们的强度只逐渐增加,随着温度的降低。低于10 K时,相应的峰强度随着温度的降低而迅速增加,表明AFM转变,而IC峰强度在低于5 K时消失。沿$c$轴的线性{Grüneisen}参数$Γ_c$显示出与磁化$M$的磁滞行为不同的磁滞行为。本文讨论了NdFe $_2$ Ga $_8$的磁性起源。
Magnetism of the Fe$^{2+}$ and Ce$^{3+}$ sublattices in Ce$_{2}$O$_{2}$FeSe$_{2}$: a combined neutron powder diffraction, inelastic neutron scattering and density functional study
在30 K以上的122铁硒化物材料中发现超导性需要了解潜在的磁相互作用。我们提出了磁性和半导体Ce $_{2}$ O $_{2}$ FeSe $_{2}$组成的边连接的铁硒四面体链的实验和理论研究相结合。结合中子衍射和非弹性散射的研究和密度泛函计算证实了最近邻的铁-硒-铁相互作用的铁磁性质的ZrCuSiAs相关的铁硒氧化物Ce $_{2}$ O $_{2}$ FeSe $_{2}$。非弹性测量提供了最近邻的Fe-Fe和Fe-Ce相互作用的强度的估计。这与密度泛函理论计算结果一致,表明Ce $_{2}$ O $_{2}$ FeSe $_{2}$的Fe-Se片层中的相关性很弱. Fe原位排斥$U_{Fe}$与所报道的砷氧化物和K $_{1-x}$ Fe $_{2-y}$ Se $_{2}$相当,它们是铁基超导体的母体。
Neutron diffraction evidence of the 3-dimensional structure of Ba2MnTeO6 and misidentification of the triangular layers within the face-centred cubic lattice
Nonconventional magnetic order in frustrated diamond lattice antiferromagnet CoAl2O4 studied by neutron diffraction and classical Monte-Carlo simulation
已知在金刚石A晶格上具有磁性Co2+离子的CoAl 2 O 4尖晶石是磁性受抑的。我们比较了在零磁场和外加磁场中测量的中子单晶衍射图与经典蒙特卡罗模型得到的衍射图。在模拟中,我们测试各种参数对衍射图案的影响:最近的,J1,和下一个最近的,J2,邻居的相互作用,磁场施加沿主要结晶方向的比率,和随机无序的A(Co 2+)和B(Al 3+)的网站。我们的结论是,到目前为止所考虑的模型解释了磁布拉格峰的加宽在零磁场和它们的各向异性响应施加磁场只有部分。由于我们的单晶体的整体性能是各向同性的,我们认为,它的微观结构,特别是<111>-孪晶界,可能是CoAl 2 O 4的非常规磁秩序的原因。
Two geometrically frustrated magnets studied by neutron diffraction
在烧绿石化合物Tb $_2$ Ti $_2$ O $_7$和Tb $_2$ Sn $_2$ O $_7$中,只有Tb $^{3+}$离子是磁性的。它们表现出相当异常的-而且,鉴于它们的化学相似性,又有着惊人的不同-磁行为,正如在环境压力和外加压力下用中子衍射所探测到的那样。Tb $_2$ Ti $_2$ O $_7$是一种协同顺磁体(“自旋液体”),在环境压力下没有长程序;然而,它在压力下变得有序。相比之下,Tb $_2$ Sn $_2$ O $_7$在环境压力下已经进入“有序自旋冰”状态。我们分析一个简单的模型,它已经清楚地表现出一些实验观察到的定性特征。总的来说,比较这两种化合物强调了在几何受挫系统中选择低温状态的小扰动的力量。
Observation of Altermagnetic Order Switching in Bulk MnTe by Polarized Neutron Diffraction
Institute for Solid State Physics, the University of Tokyo(东京大学固体物理研究所);RIKEN Center for Emergent Matter Science (CEMS)(理化学研究所新兴物质科学中心);Institute of Materials Structure Science, High Energy Accelerator Research Organization(高能加速器研究机构物质结构科学研究所);Trans-scale Quantum Science Institute, the University of Tokyo(东京大学跨尺度量子科学研究所)
First order valence transition: Neutron diffraction, inelastic neutron scattering and x-ray absorption investigations on the double perovskite Ba2PrRu0.9Ir0.1O6
Probing low temperature non-equilibrium magnetic state in Co$_{2.75}$Fe$_{0.25}$O$_{4+δ}$ spinel oxide using dc magnetization, ac susceptibility and neutron diffraction experiments
利用同步辐射X射线衍射(SXRD)、直流磁化、交流磁化率、中子衍射和中子退极化等技术研究了Co $_{2.75}$ Fe $_{0.25}$ O $_4$铁氧体的低温晶格结构和磁性。通过在高碱性介质中化学共沉淀Fe和Co硝酸盐溶液,然后在200- 900 $^\circ$ C温度范围内热退火沉淀物来制备样品。室温下SXRD图谱的Rietveld精修表明,在200-600 $^\circ$ ℃温度下退火的样品具有两相立方尖晶石结构。在700 $^\circ$ C和900 $^\circ$ C(CF 90)退火的样品最适合单相晶格结构。在5-300 K温度范围内的中子衍射图的精细化证实了在600 $^\circ$ C下退火的样品的反铁磁(AFM)Co $_3$ O $_4$和亚铁磁(AFM)Co $_{2.75}$ Fe $_{0.25}$ O $_4$相以及CF 90样品的Co $_{2.75}$ Fe $_{0.25}$ O $_4$的单相。磁性测量显示出非平衡磁性结构,由高温FIM相和低温AFM相组成。磁性相对磁场敏感,其中高温相通过增强低温AFM相而在较高磁场下被抑制,而与样品的退火温度无关。