Vortex dynamics and magnetic anisotropy in RuSr[sub 2]GdCu[sub 2]O[sub 8].

Polycrystalline samples of RuSr[sub 2]GdCu[sub 2]O[sub 8] with a magnetic ordering temperature (T[sub M]=135 K) and a resistively determined superconducting onset temperature (T[sub c]=45 K) were synthesized using a solid-state reaction. Transport and magnetic measurements indicated coexistence of weak ferromagnetic-like order and superconductivity at low temperatures. A novel radio-frequency (rf) resonant technique was employed to probe the mixed state response. The results clearly indicate that in the superconducting state (T<T[sub c]), the rf response is dominated by the flux lattice dynamics and in the normal state (T[sub c]<T<T[sub M]), the data are consistent with transverse susceptibility exhibiting sharp peaks at characteristic switching and anisotropy fields. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]