Magnetic phase transitions in the double spin-chains compound LiCu2O2

Abstract

We report high-resolution X-ray diffraction, muon-spin-rotation spectroscopic and specific heat measurements in the double spin-chains compound LiCu2O2. The X-ray diffraction results show that the crystal structure of LiCu2O2 is orthorhombic down to T=10K. Anisotropic line-broadening of the diffraction peaks is observed, indicating disorder along the spin chains. Muon-spin relaxation and specific heat measurements show that LiCu2O2 undergoes a phase transition to a magnetic ordered state at T1∼24K. The specific heat data exhibits a second λ-like peak at T2∼22.5K, which increases with increasing magnetic field in a similar way to that found in spin-ladder compounds.