Magnetic properties of a new iron lead vanadate Pb2FeV3O11

Temperature dependence of dc/ac magnetization and electron paramagnetic resonance (EPR) spectra of Pb2FeV3O11 iron lead vanadate has been investigated. The dc magnetic measurements have shown the presence of antiferromagnetic interactions with Curie–Weiss temperature, TCW = −15.2 K, in the high temperatures range while the field cooled (FC) magnetization revealed a maximum at TN = 2.5 K which coincides with a long range magnetic ordering. Temperature dependence of χ′ has shown a maximum at the same temperature. EPR spectrum of Pb2FeV3O11 at room temperature is dominated by nearly symmetrical, very intense and broad resonance line centered at geff ∼ 2.0 that could be attributed to the correlated system of iron ions. The temperature dependence of magnetic resonance parameters (amplitude, g-factor, linewidth, integrated intensity) has been determined in the 4–300 K range and it suggests the existence of short range correlated spin system up to high temperatures. The temperature dependence of the amplitude of the resonance line has shown a pronounced maximum at 12.5 K that indicates on the existence of two subsystems of weakly and strongly coupled iron pairs. Comparison of dc magnetic susceptibility and EPR integrated intensity points to the presence of correlated spin agglomerates that play an important role in determination of the magnetic response of Pb2FeV3O11.

► We study magnetic properties of a new iron lead vanadate Pb2FeV3O11.
► We employ dc/ac magnetic susceptibility and electron paramagnetic resonance methods.
► We detected the existence of AF phase below 2.5 K.
► EPR spectrum reflects the presence of two types of Fe3+–Fe3+ pairs.
► EPR and magnetic susceptibility are complementary methods revealing different aspects of magnetic interactions.