Abstract
The RuSr2GdCu2O8 Ru-1212 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. The c-axis aligned powder can be achieved at room temperature using the field-rotation method where the tetragonal c-axis is perpendicular to the aligned magnetic field Ba and along the rotation axis. The anisotropic temperature dependence of magnetic susceptibility for the aligned powder down to 2 K indicates weak anisotropy with Xc > Xab at room temperature due to strong anisotropic Gd contribution and Xc < Xab below 185 K where strong Ru anisotropic short-range exchange interaction overtakes the Gd contribution. Anisotropic diamagnetic superconducting intragrain shielding signal of aligned microcrystalline 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 μm), long penetration depth (λab ~ 0.6 μm, λc ~ 2 μm) and the two-dimensional (2D) character of CuO2 layers.