Spin orientation in spin frustrated system LiCu2O2LiCu2O2

We have systematically measured susceptibility, angle dependent magnetization and specific heat on LiCu2O2LiCu2O2 single crystal. When magnetic field (H) is rotated within ab plane, a twofold symmetry in magnetization is observed at 50 and 100 K under H=5T, while a jump in magnetization is observed at certain angle with the twofold symmetry at 10 K. Specific heat shows two successive transitions at Tc1=24.7K and Tc2=23K, respectively. The first one at Tc1Tc1 shows antiferromagnetic (AFM) nature, while the second one at Tc2Tc2 shows ferromagnetic (FM) behavior. These behaviors can be interpreted by the recently reported magnetic structure, and confirm the magnetic structure through another way.