Anomalous Hall Effect in Superparamagnetic Co-(La,Sr)TiO$_{3}$ Thin Films

We performed a systematic study of the magnetic properties and the Hall effect on 5{\%} cobalt doped (La, Sr)TiO$_{3 }$thin films grown by pulsed laser deposition. The superparamagnetic nature of the system is established by several protocols of magnetic measurements. Nevertheless, the anomalous Hall effect (AHE) is observed in the system, the Hall resistivity vs magnetic field loops being found to be identical to the magnetic hysterisis loops. This once again (Phys. Rev. Lett. 92, 166601 (2004)) highlights the limitations of AHE as a tool to test the intrinsic nature of ferromagnetism in a diluted magnetic system. Possible reasons for the origin of the AHE in our system are discussed.