Study of low temperature ferromagnetism, surface paramagnetism and exchange bias effect in α-Fe1.4Ga0.6O3 oxide

The compound α-Fe1.4Ga0.6O3 has been prepared by mechanical alloying of α-Fe2O3 and β-Ga2O3 and subsequent heating under vacuum condition. X-ray diffraction, Raman and Mössbauer spectroscopy confirmed stabilization of the material in rhombohedral phase. A remarkable change in the magnetic ordering has been found by substitution of non-magnetic Ga atoms in α-Fe2O3. The ferromagnetism in α-Fe1.4Ga0.6O3 is found to be more soft and enhanced in comparison to α-Fe2O3. The samples also exhibited features of exchange bias, low temperature surface paramagnetism, and suppression of Morin transition. Nano-sized grains and alloying process of the material affected these features up to certain extent. The results of magnetic measurements are highly interesting for designing metal doped α-Fe2O3 based ferromagnet for room temperature applications.