Local spin reversal and associated magnetic responses in Ga-substituted Pb-hexaferrites

► The Fe3+ spin moment at 2a site undergoes switching in its direction with temperature. ► The weakening of superexchange interaction is caused by substitution of Ga ions. ► The selective local spin reversal is correlated with the broad ac susceptibility response. ► The PM-FM transition (at ∼325 K) is followed by the local spin reversal at lower temperature.