Persisting correlation between electrical transport and magnetic dynamics in M-type hexaferrites

Abstract In this work, we present frequency-dependent magnetic susceptibility and dc electric transport properties of three different compositions of hexaferrite Ba1−xPbxFe12−yAlyO19 single crystals. We found a correlation between the activation energies of the dc electric transport and the ac magnetic susceptibility which persists over the whole studied range of aluminium substitution x = 0 to 3.3. This result is discussed in the context of charged magnetic domain walls, the pinning of which is determined by charge carriers activated across the transport gap. Our work points toward a general relaxation mechanism in ferrimagnetic semiconductors that directly affects the dynamic magnetic properties via electrical transport.