Anomalous Hall effect in anatase Co:TiO2 ferromagnetic semiconductor

Abstract

The observation of the anomalous Hall effect (AHE) in Co-doped TiO2 ferromagnetic semiconductor in the anatase phase is reported. An AHE is observed with magnetic hysteresis consistent with remanence and coercivity obtained from magnetometry data. The anatase films also have reasonable mobility (∼17cm2∕Vs) at room temperature and carrier density of ∼5×1018cm−3. The AHE in such films with relatively low carrier density gives prospects to test whether the ferromagnetism in this oxide semiconductor is carrier mediated using a field effect device configuration.

Structural, optical, and magnetic properties of polycrystalline Co-doped TiO2 synthesized by solid-state method

“…The authors detected room temperature ferromagnetism only in samples containing less than 15 at.% of Mn, 8 at.% of Fe, and 6 at.% of Co. There are many reports reported an intrinsic origin for ferromagnetism [23][24][25]. However, there are also many reports claiming an extrinsic origin, such as the observation of secondary phases [26,27].…”

Anomalous Hall effect in sputter-deposited CoxTi1−xO2–δ films

“…The low resistivity reflects a higher density of oxygen vacancies. Note that the value of r AH , given by the offset from a linear r xy , is of the same order of magnitude as that reported elsewhere for low conductivity (Ti,Co)O 2 films [29]. Fig.…”

Room Temperature Ferromagnetic Semiconductor Rutile Ti1-xCoxO2-δEpitaxial Thin Films Grown by Sputtering Method

“…A room temperature (RT) ferromagnetic semiconductor Ti 1-x Co x O 2-δ is one of the promising materials for semiconductor spintronics, 1,2) exhibiting large magneto-optical effect 3,4) and anomalous Hall effect [5][6][7][8][9] with high Curie temperature ~600 K. 10) Its device implementation has also been demonstrated as a tunneling magnetoresistance device operable at up to 200 K, 11) that is the highest operation temperature among spintronics devices using ferromagnetic semiconductors. Until now, several sophisticated methods such as pulsed laser deposition method (PLD) and molecular beam epitaxy have been exploited to synthesize Ti 1-x Co x O 2-δ since the resultant high quality epitaxial thin films are useful to reveal its unresolved fundamental properties as a ferromagnetic semiconductor.…”