Magnetic and magnetotransport properties of Ba ₂FeMoO ₆ pulsed laser deposited thin films

Phase pure Ba ₂FeMoO ₆ thin films were grown by pulsed laser deposition at substrate temperatures ranging from 600 to 900 °C, and the structural, magnetic, and magnetotransport properties were investigated. The grain size, the conductivity, the saturation magnetization, and the coercive field all increase with increasing growth temperature, while the Curie temperature remains relatively constant. All samples showed negative magnetoresistance which is consistent with the half metallic property of double perovskites. Interestingly, the samples grown on the higher temperature substrates showed a small low-field positive magnetoresistance which is not understood. We also have observed an anomalous Hall effect, due to spin-polarized itinerant electrons, in which the saturation field of the hole-like anomalous portion decreases with increasing temperature and at higher temperatures manifests a negative slope (ordinary Hall effect) indicative of negative charge carriers.