Epitaxial Pb–Fe–O film with large planar magnetic anisotropy on (0001) sapphire

Abstract

Epitaxial films (1.7 μm thick) with the composition PbFe12.9O22.9 and hexagonal lattice parameters a=5.12 Å and c=23.67 Å have been pulsed laser deposited at 600 °C in 50 mTorr of O2 onto single-crystal (0001) sapphire substrates. Epitaxy was determined using standard powder x-ray diffraction (XRD) and grazing incidence XRD. The films were deposited using a single-phase polycrystalline PbFe12O19 target. The composition of the films is PbFe12.9O22.9, which was measured using Rutherford backscattering spectrometry. Static magnetic measurements were performed using a vibrating sample magnetometer and SQUID magnetometer in order to measure magnetic anisotropy, magnetic remanence (Mr), coercive field (Hc), and saturation magnetization (4πMs) of the films. The PbFe12.9O22.9 films exhibit magnetically isotropic behavior in the film plane with remanence ratio (Mr/Ms) and Hc values of 88±2.9% and 2500±97 Oe, respectively. However, the films are anisotropic with respect to the film normal such that the c axis is a magnetically hard direction and all directions normal to the c axis are magnetically easy (i.e., a planar anisotropy field, HA, with an estimated magnitude of 77.5 kOe). The 4πMs value for the films is 630 Gauss at room temperature.