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

Epitaxial films (1.7 mu m thick) with the composition PbFe12.9O22.9 and hexagonal lattice parameters a=5.12 Angstrom and c=23.67 Angstrom have been pulsed laser deposited at 600 degrees C in 50 mTorr of O-2 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 (M(r)), coercive field (H-c), and saturation magnetization (4 pi M(s)) of the films. The PbFe12.9O22.9 films exhibit magnetically isotropic behavior in the film plane with remanence ratio (M(r)/M(s)) and H-c 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, H-A, with an estimated magnitude of 77.5 kOe). The 4 pi M(s) value for the films is 630 Gauss at room temperature. (C) 1997 American Institute of Physics.