Weak ferromagnetic transition in a La2CuO4 single crystal in a time-varying field

The weak ferromagnetic phase transition in an antiferromagnetic La2CuO4 single crystal in a pulsed magnetic field of duration 33 ms is investigated by measuring the sample conductivity. The transition is observed to proceed in two steps in the ascending field and with a single jump in the descending field. It is shown that this fact is difficult to treat within the scope of previously proposed models of the magnetic structure of lanthanum cuprate. Some possible ways of refining the conventional model are suggested, along with mechanisms that could account for the observed two-step character of the transition. An analogy is drawn with the like behavior of the magnetization of FeCO3 in the so-called “mixed” state.