Magnetic Instabilities in the Quasi-One-Dimensional K 2 Cr 3 As 3 Material with Twisted Triangular Tubes.

The magnetic response of a frustrated K 2 Cr 3 As 3 sample having triangular arrays of twisted tubes has been studied by means of dc magnetization measurements as a function of the magnetic field ( H ) at different temperatures ranging from 5 K up to 300 K. Looking at the magnetic hysteresis loops m ( H ), a diamagnetic behavior of the sample was inferred at temperatures higher than 60 K, whereas at lower temperatures the sample showed a hysteresis loop compatible with the presence of ferrimagnetism. Moreover, spike-like magnetization jumps, both positive and negative, were observed in a narrow range of the magnetic field around 800 Oe, regardless of the temperature considered and they were compared with the theoretical predictions on frustrated systems. The field position of the magnetization jumps was studied at different temperatures, and their distribution can be described by a Lorentzian curve. The analogies between the expected features and the experimental observations suggest that the jumps could be attributed to the magnetic frustration arising from the twisted triangular tubes present in the crystal lattice of this compound.