Effect of oxidation on the magnetic properties of unprotected TbFe thin films

Abstract

Amorphous Tb-Fe thin films prepared by dual magnetron cosputtering were exposed to air at 200 °C in order to investigate the evolution of the films as they oxidize. Magnetic properties of the films were measured using a vibrating-sample magnetometer and torque magnetometer and are interpreted in light of the structure of the films as revealed by Auger electron spectroscopy and composition-depth profiling. This leads to a detailed and self-consistent description of the oxidation process. At first a uniform and homogeneous oxidation layer grows from the surface toward the substrate. This layer has a high magnetization and low intrinsic anisotropy and consists of an intimate mixture of oxidized Tb and metallic TbxFe(1−x). The initially high intrinsic anisotropy of the unoxidized region decreases relatively quickly, while the composition changes only slowly as this region shrinks. When the oxidation layer reaches the substrate, two oxide phases (Fe2O3 and Tb2O3) begin to grow at the surface exposed to air.

The influence of oxygen on the thermal mixing of Cr and GdxOy thin films

“…van Dover et a1. 13 found that the oxidation of TbFe started at the surface, with Tb oxidizing first. This was followed by the oxide growing inwards and the subsequent oxidation of Fe.…”

M-O Properties of Pulsed Laser Annealed Tb-Fe-Co Thin Films

“…Ageing and thermal annealing studies of RE-TM have been carried out by a number of investigators, who propose that the resulting changes in hysteresis properties were due to either the oxidization [5] or crystallization [6] of the films. In the reports where oxidization was demonstrated, Auger electron spectroscopy has revealed an oxidized zone, showing hysteresis properties similar to that displayed in fig.…”

The Native Oxide Effects on the Optical Properties of TbFe2

“…Allen and Connell [3] studied oxidation effects on the optical and magneto-optic properties of 110 nm-thick amorphous Tb x Fe 1Àx (x ¼ 0:21). They found that the oxide layer grew to a thickness of about 50 A within 10 min at 22 C. Dover et al [4] investigated the oxide effects on the magnetic properties of amorphous thin films of Tb-Fe alloys. They estimated the thickness of the oxide layer using Auger electron spectroscopy (AES).…”