Magnetic and transport properties of Ni2MnGa–BaTiO3 metal–insulator particulate composite with percolation threshold

Here we report the magnetic and transport properties of the metal/insulator (fNMG)Ni2MnGa/(1 − fNMG)BaTiO3 composites. The X-ray diffraction study confirms the formation of both the phases in composite. The microstructure reveals that the conducting Ni2MnGa particles are well dispersed in an insulating BaTiO3 matrix. Temperature dependent magnetization shows two transitions one above 300 K and other below 150 K. The temperature dependence resistivity near the percolation threshold fNMG = 0.4 had drastic changes which is higher than the fNMG = 0.5. Also the negative magnetoresistance effect was observed for the studied materials. We suggest that magnetic and transport properties at the percolation threshold can be adjusted by the strain from the surrounding insulator particle.

► The Ni2MnGa–BaTiO3 type composites were first time prepared by solid state reaction.
► Temperature dependent magnetic properties reveal two kinds of transitions in these composite.
► The present materials show negative magnetoresistance effect.
► The present studies on magnetic and electrical transport of metal/insulator (NMG/BTO) composites shows the resistivity change associated to filamentary conducting path at percolation threshold.