Structural, magnetic and electrical properties of Heusler alloy Cr3Al

Abstract

Materials that can provide highly spin polarized electrons or current are very relevant for spintronics device applications. Recent studies have found an interesting class of spintronics materials called spin gapless semiconductor (SGS) which has zero gap for one spin channel and a small band gap for other spin channel. Such a band structure facilitates really high spin polarization. The binary Heusler, Cr3Al with DO3 type structure is predicted to exhibit SGS characteristics. Several experiments are done on the preparation and characterization of Cr3Al films, but no experimental studies are done on bulk crystalline form. Here we have successfully synthesized Cr3Al alloy in bulk form. The room temperature XRD and Rietveld refinement studies indicate that the annealed Cr3Al is formed in DO3 type structure. The SEM images confirm the prepared samples are in single phase. The temperature dependent resistance studies reveal the weak semiconducting behavior of the prepared sample. Temperature and field dependent magnetization studies indicate ferrimagnetic order above 300 K with very small moment. The observations from the magnetization studies are very different from the previous thin film reports that confirms the antiferromagnetic ordering.