Dramatic Reduction of FMR Linewidth in Epitaxial Pb(ZrTi)O $_{3}$ -NiFe$_{2}$ O$_{4}$ Nanocomposite Films

Self-assembled nanocomposite Pb(Zr
_0.52
Ti
_0.48
)O
₃
-NiFe
₂
O
₄
films have been grown on the (001)-oriented MgAl
₂
O
₄
substrate by a 90° off-axis magnetron sputtering method. X-ray diffraction shows that both Pb(ZrTi)O
₃
and NiFe
₂
O
₄
phases are epitaxial with a 1-3 dimensional embedding composite structure. The vertical lattice mismatch between the Pb(ZrTi)O
₃
and NiFe
₂
O
₄
phase is only 0.65%, indicating almost perfect matching of both phases and low defect concentration. Magnetization measurement shows that the coercive field is 274 Oe and linear extrapolation of the in-plane magnetization yields a uniaxial anisotropy field of ~1.3 kOe for a 1200 nm-thickness sample. The peak-to-peak ferromagnetic resonance (FMR) linewidth of the film is about 271 Oe, therefore, suitable for nonreciprocal RF/microwave devices.