Observation of Field-induced Anomaly in High-field Magnetization on a Complex Spin-Driven Multiferroic Compound, LiCu2−z Zn z O2

Abstract

We performed high-field magnetization measurements in the pulse magnetic fields up to 55 T at low temperatures on a doped LiCu2−z Zn z O2 (z=0.07). When H // c-axis, one anomaly was clearly observed in \(\frac{dm}{dH}\) curves at ∼9 T. The anomaly broadens as temperature increases and disappears at ∼15 K, which is close to the critical temperature of spiral spin phase and the formation of isolated spin-dimer. Interestingly, an additional peak shows up at 4.2 K, indicating a possible boundary at ∼5 K. On the other hand, when H // a-axis, one broad anomaly can be distinguish which is centered around 11.8 T. However, this anomaly only appears at T≤5.5 K, which is much lower than 15 K, indicating the origin of this anomaly could be different with those in H // c-axis. It is probably comes from the broken one-dimensional chain and the complex inter-chain interactions.