Microwave absorption measurements in the complex perovskite Pb(Fe0.5Ta0.5)O3: Detection of short-range orderly regions

An electron paramagnetic resonance (EPR) study of the complex perovskite Pb(Fe0.5Ta0.5)O3 (PFT) at X-band (8.8–9.8 GHz) is presented. The EPR spectra show a single broad line in the 300–480 K temperature range, attributable to Fe3+ (S = 5/2) ions. The temperature dependence of the EPR parameters: the peak-to-peak linewidth (ΔHpp), the resonance field (Hres) and the integrated intensity (IEPR), suggests the existence of short-range magnetic correlations; which are associated with the presence of small orderly regions of iron ions in B-sites of the perovskites-type structure, and that they give origin to formation of iron clusters. Low-field microwave absorption (LFMA) is used to give further knowledge on this material; where this technique also gives evidence of these short-range orderly regions.

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► LFMA spectra showed straight lines with positive slope and non-hysteretic traces.
► The spectral changes for the plot of the slope vs. temperature give evidence of the formation of iron clusters.
► These small orderly regions of iron ions generate short-range magnetic correlations, and that they produce changes in dynamics of microwave absorption.