Evidence of weak ferromagnetism in Pb(Fe_2/3W_1/3) O₃ powders by means of non-resonant microwave absorption

We report on the effects of temperature and dc magnetic field on non-resonant microwave absorption measurements at X-band (8.8-9.8 GHz) in Pb(Fe_2/3W_1/3)O₃ powders, for the 294-425 K temperature range. Two techniques are used: the magnetically modulated microwave absorption spectroscopy (MAMMAS) and the low-field microwave absorption (LFMA). MAMMAS response showed distinctive features associated with para-antiferromagnetic transition at T _N =334.3 K, and below T _N a weak ferromagnetism is also observed, and it is attributed to canting of Fe⁺³ ion sublattices in the antiferromagnetic matrix. The low-field microwave absorption (LFMA) is used to give further knowledge on this material, where this technique also gives evidence of the magnetic transition, suggesting a weak ferromagnetism at room temperature.