Magnetic & transport properties of quaternary Heusler compounds CoZMnGa (Z=Fe,V)

We present here the magnetic properties as well as the electrical transport properties of two quaternary Heusler alloys (QHA), CoFeMnGa and CoMnVGa. The compound CoFeMnGa has a significantly high Curie temperature of 620 K, while CoMnVGa orders magnetically below 220 K. Our study presents a noticeable change in the temperature dependent resistivity of CoFeMnGa around 320 K, where the sample shows a semiconductor to metal transition when temperature is decreased. On the other hand, CoMnVGa shows a metallic behaviour for a wide temperature range. However, above 250 K, the resistivity shows a saturation tendency, which coincides with the magnetic transition temperature. Both the compounds follow the ‘Zt – 24’ type Slater-Pauling rule indicating that they can be prospective candidates for half-metallic magnetic materials.