Preparation and thermomagnetic properties of Ti-doped MnBi thin films

Ti-substituted MnBi thin films have been prepared on glass substrates by a vacuum deposition technique, and studies of magnetic, magnetooptic, and thermomagnetic properties of the films have been made. The nominal composition range of Mn1-xTixBi was x=0.1 to 0.4. The films were well oriented with the c-axis perpendicular to the film plane. The Curie point of the quenched high temperature phase (qhtp) decreased with increasing Ti-concentration, but that of the low temperature phase (ltp) was not altered by Ti-doping. The best Kerr rotation obtained for the qhtp films with x=0.4 was 0.5 deg at 6328 Å. Both the Faraday and the Kerr rotation of the ltp and qhtp films decreased with increasing the Ti concentration. The time constant associated with the qhtp to ltp transformation was 10³sec at 180°C for x=0.4. Curie point writing experiments with a helium-neon gas laser showed that the writing threshold of the qhtp film was about one third of that of the ltp film.