Transition from paramagnetism to ferromagnetism through additional hole doping of non-magnetic antimony in iron doped tellurium alloy

Abstract We have found an enhancement in the magnetic ordering of tellurium as a result of doping it with iron along with an additional doping of a non-magnetic element antimony. A weak ferromagnetism is observed from the magnetization hysteresis which can pave the way for new kinds of magnetic semiconductors. Using the modified solid state approach, we synthesized bulk alloys of Fe-doped tellurium with co-doping of Sb having general form Fe 0.05 (Te) 1−x Sb x ; x = 0 and 0.03 and analyzed the sample for their structural, electrical and magnetic properties. Electrical resistivity measurements with varying external magnetic field has been carried out and it shows semiconducting nature for both samples. The conduction mechanism in the high temperature region follows small polaron hopping (SPH) model whereas in the low temperature region, variable range hopping (VRH) model is found to fit the data. Traditionally, though tellurium is diamagnetic in nature, x = 0 sample presents itself as a paramagnetic material as evident from the magnetization measurements. On the other hand, x = 0.03 sample has a small hysteresis which is brought about by the substitution of Sb. A negative to positive crossover is observed in the magnetoresistance plot of both samples which can be co-related to transition from variable range hopping mechanism to thermally activated hopping mechanism.