Temperature dependence of magnetic moment of rare earth ions in ErFeO and NdFeO single crystals.

The interaction between rare earth and iron spins in rare earth orthoferrites leads to remarkable phenomena, such as the spin-flip process. This is despite the rare earth spins not being magnetically ordered. Instead, they are polarized by the ordered iron spins. The interaction between the two spin families is not well understood. This study reports the temperature dependence of the net magnetic moment for rare earth spins, by measuring the overall magnetization for ErFeO and NdFeO single crystals. The obtained temperature dependence can be described well using a model based on the mean field theory, giving tanh(const./) temperature dependence. This functional dependence is not disrupted by the spin-flip transition as the crystals are cooled.