Structure-dependent magnetization in helimagnetic YMn2O5

YMn₂O₅ compounds have been important for industrial applications due to their unique nature of ferroism. In this study, two YMn₂O₅ samples with different phases are prepared, one is orthorhombic (OT) and the other is hexagonal (HX) in structure, for investigating the structure dependency of magnetic properties. By changing the sintering temperature from 1100 to 1400°C, the crystal structure of YMn₂O₅ is transformed from OT phase to HX phase. Based on the data of temperature-dependent magnetization M(T), the magnitude of magnetic moment in the HX phase is one order higher than that of the OT phase. Furthermore, the field-cool and zero-field-cool M(T) show a splitting around 50 K for both samples, indicating a common feature of spin-canted state. In conjunction with the results of low-temperature M--H curves, it is concluded that the YMn₂O₅ sample with the HX structure has one order higher magnetization at low temperature than that of the OT structure, which should have wide impact to future applications.