Pb cation induced low-temperature crystallization of (Ba•Pb) hexa-ferrite thin films

We have studied the low-temperature crystallization of (Ba•Pb) hexa-ferrite thin films using real time synchrotron X-ray scattering, anomalous X-ray scattering, and vibrating sample magnetometer. The crystallization temperature of amorphous (Ba•Pb) hexa-ferrite film (300-Å-thick, ∼530°C) was much lower than that of amorphous Ba hexa-ferrite film, ∼750°C. The crystalline (Ba•Pb) hexa-ferrite phase was formed by solid phase transformation of the interfacial crystalline Fe₃O ₄ phase through the diffusion of Ba or Pb cations. The low crystallization temperature of the (Ba•Pb) hexa-ferrite phase was due to the lower diffusion activation barrier of Pb cations than that of Ba cations. The small grain size (∼40 nm in diamter) and comparable magnetic properties (Ms : 337 emu/cm³, iHc : 1.60 kOe) of the crystallized (Ba•Pb) hexa-ferrite film also demonstrate its potential possibility for high-density recording media.