Competition between the singlet-spin liquid state and the magnetic ground state in a two-chain spin-1/2 antiferromagnetic ladder compound LaCuO2.5: A 63Cu NMR study

A magnetically isolated cuprate spin-ladder system: synthesis, structures, and magnetic properties

Two magnetically isolated cuprate spin ladders have been synthesized. Their crystal structures and preliminary investigation into the magnetic properties were reported.

Thermodynamic properties in the approach to the quantum critical point of the spin-ladder material Na2Co2(C2O4)3(H2O)2

Magnetic susceptibility and heat capacity measurements as a function of temperature on a single-crystal sample of a spin-ladder material, Na2Co2(C2O4)3(H2O)2, are reported. Principal susceptibilities, parallel and perpendicular to the ladder direction, respectively, show broad maxima around 22 and 17 K. Both susceptibilities decay exponentially down to about 5 K and thereafter they are essentially independent of temperature. These findings amount to a signature of a quantum phase transition from a spin-liquid to Néel ordered state previously predicted theoretically. No anomaly is found in the heat capacity around the transition temperature.