Experimental Observation of Room-temperature Anomalous Hall Mobility and Positive Magnetic Hysteresis in Amorphous Fe-Dy-O Thin Films*

Fe-Dy-Tb-O thin film system was recently reported with very high transparency, conductivity and room temperature ferromagnetism driven by partially filled d - and f - subshells. Here, we have synthesized and studied the Fe-Dy-O thin films. The thin film system was prepared by e-beam evaporation and its structural, transport, magnetic and optical characterizations were performed. The as-grown films were amorphous, as evidenced by transmission electron microscopy and X-ray scattering. X-ray absorption spectra revealed a progressive oxidation of thin films on reducing the dimension. The films showed high ordinary (~10 cm²/V-s) and anomalous (~10² cm²/V-s) Hall mobility with n-type semiconducting behavior. Cryogenic magnetic behaviors evinced the existence of spin-glass-like transition at 79 K. Positive hysteresis loop and transverse magneto-resistivity up to 4% in the magnetic field of 5 T were observed at room temperature. Room-temperature optical studies showed the existence of a band gap of 2.42 eV in the visible range. These unique set of properties make the system a rich toolbox for not only understanding condensed matter behavior but also realizing multifunctional devices.