The powder alignment method is used to investigate the anisotropic physical properties of the weak-ferromagnetic superconductor system RuSr2RCu2O8 (R = Pr, Nd, Sm, Eu, Gd, Gd0.5Dy0.5). The RuSr2GdCu2O8 cuprate is a weak-ferromagnetic superconductor with a magnetic ordering of Ru moments at TN(Ru) = 131 K, a superconducting transition in the CuO2 layers at Tc = 56 K, and a low temperature Gd antiferromagnetic ordering at TN(Gd) = 2.5 K. Due to weak magnetic anisotropy of this tetragonal system, highly c-axis aligned microcrystalline powder (diameter ~ 1-10 $μ$m) in epoxy can be obtained only for R = Eu and Gd through the field-rotation powder alignment method where c-axis is perpendicular to the aligned magnetic field Ba = 0.9 T and parallel to the rotation axis. For smaller rare earth compound R = Gd0.5Dy0.5, powder alignment can be achieved using the simple field powder alignment method where c-axis is partially aligned along the aligned magnetic field. The anisotropic temperature dependence of magnetic susceptibility for the c-axis aligned powders exhibit weak anisotropy with $χ_{c} > χ_{ab}$ at room temperature due to anisotropic rare earth, Eu and Gd, contribution and crossover to $χ_{c} < χ_{ab}$ below 190 K where strong Ru anisotropic short-range exchange interaction overtakes the rare earth contribution. Anisotropic diamagnetic superconducting intragrain shielding signal of aligned microcrystalline RuSr2GdCu2O8 powder-in-epoxy below vortex lattice melting temperature at 39 K in 1-G field is much weaker than the intergrain polycrystalline bulk sample signal due to the small grain size (d ~ 1-10 $μ$m), long penetration depth ($λ_{ab}$ ~ 0.55 $μ$m, $λ_{c}$ ~ 0.66 $μ$m) and the two-dimensional (2D) character of CuO2 layers.
On the dc Magnetization, Spontaneous Vortex State and Specific Heat in the superconducting state of the weakly ferromagnetic superconductor RuSr$_{2}$GdCu$_{2}$O$_{8}$
用球共振方法研究了RuSr $_{2}$ GdCu $_{2}$ O $_{8}$，Ru $_{1-x}$ Sr $_{2}$ GdCu $_{2+x}$ O $_{8}$（x = 0.3）和RuSr $_{2}$ Eu $_{2-x}$ Ce $_{x}$ Cu $_{2}$ O $_{10}$（x = 0.5）化合物中的约瑟夫森等离子体.对于铁磁RuSr $_{2}$ GdCu $_{2}$ O $_{8}$，约瑟夫森等离子体在低频区域（在T $\ll$ $T_{c}$处约8.5 cm $^{-1}$）中被观察到，而对于非铁磁Ru $_{1-x}$ Sr $_{2}$ GdCu $_{2+x}$ O $_{8}$，其增加到35 cm $^{-1}$（x = 0.3），这表示铁磁RuO $_{2}$阻挡层处的约瑟夫森耦合的大幅减少。等离子体的温度依赖性不偏移到零频率（{ \it，即}）。$j_{c}$ = 0），表明在这些化合物中没有从0-相到$π$ -相的转变。峰的温度依赖性和振子强度不同于其他非磁性铜氧化物，并讨论了这些异常的来源。
The magnetic state of 1212-type ruthenocuprate in magnetocaloric and magnetoresistivity measurements of polycrystalline samples of RuSr2Gd1-xCexCu2O8 and Ru1-xSr2GdCu2O8
利用磁热实验和交流磁化率测量，研究了超导Ru 1-xSr 2GdCu 2 O 8（x=0，0.02）和非超导RuSr 2Gd 1-xCexCu 2 O 8（x=0.07，0.1）的磁性质.等温磁热系数M_{T}（B）在宽的温度范围内呈现正值（20 K <T<231 K）和磁场（0<B<13 T），即也处于磁有序状态（对于RuSr 2GdCu 2 O 8，T_{m} =132 K;对于RuSr2Gd0.93Ce0.07Cu2O8，T_{m} =150 K），这表明随着磁场的增加，系统的磁熵没有增加。在T_{m}附近的温度下观察到RuSr 2GdCu 2 O 8的M_{T}（B）依赖性的最大值，这表明所获得的磁关联具有铁磁特性。由于M_{T}假设在整个研究温度范围内，零磁场下的极限值为零，因此没有发现自发铁磁有序。比热的温度依赖性揭示了磁场诱导的正温度漂移的异常与磁转变的Ru自旋系统。M_{T}（B）相关性和磁阻数据表明，磁系统可能是不均匀的。
Coexistence of ferromagnetism and superconductivity in the hybrid ruthenate-cuprate compound RuSr_2GdCu_2O_8 studied by muon spin rotation (μSR) and DC-magnetization
The characteristics of the superconducting and magnetic phases in the polycrystalline samples of ruthenocuprates of nominal compositions RuSr2GdCu2O8, Ru0.98Sr2GdCu2O8 and Ru0.5Sr2GdCu2.5O8-d
本文研究了名义成分为RuSr_2GdCu_2O_8、Ru0.98Sr_2GdCu_2O_8和Ru0.5Sr_2GdCu_2.5O_8-d的超导铜氧化物的电阻率随温度的变化关系，以确定超导转变的磁场依赖特性。的Ru/Cu比在母体RuSr 2GdCu 2 O 8的显着减少的效果被证实为相关的超导相的稳定。在比较的特性中的注意到的差异被解释为可能的非均匀成核的超导相在母体xenocuprate。RuSr 2GdCu 2 O 8和Ru0.98Sr2GdCu2O8中的相各向异性，在化合物Ru磁性的存在下，似乎是Hc 2（T）相线显著软化的原因。一个异常降低的磁阻率观察到在约。10 K范围以上的超导转变的开始，这可能表明在样品中的增强的超导波动的存在。温度的正向磁场偏移限制了Ru亚晶格的磁有序态的磁阻和比热特征，这表明探测样品中存在的有效金属类导电通道中铁磁Ru相互作用的影响。的Ru0.5Sr2GdCu2.5O8-d的超导特性揭示了一个显着的贡献的Gd顺磁信号在低温下，解释为一个显着的各向异性的超导相的存在。它的结论是，Ru-Cu取代相的Cu 2 O3-Cu 2 O3
