Element-specific magnetic behavior of FeCrMnCoNi, MnCoNi, CrCoNi thin films

Multi principal element alloys (MPEA) show exceptional mechanical properties compared to conventional alloys and recently, studies have highlighted their intriguing magnetic properties such as presence of spin glass, ferromagnetism, superparamagnetism etc. Theoretical first principles studies of equiatomic MPEA consisting of 3d transition elements have proposed that magnetic interactions can drive the atomic ordering. In this study, we investigate magnetic behavior of equiatomic FeCrMnCoNi, CrCoNi and MnCoNi films. Our studies show 2-3 orders of magnitude increase in the magnetic moment compared to bulk sample for FeCrMnCoNi and MnCoNi. Additionally, while FeCrMnCoNi showed ferromagnetic behavior, spin glass transition was observed for MnCoNi. No ferromagnetic ordering was observed for CrCoNi for the measured temperature range of 60-400K. For FeCrMnCoNi, element-specific X-ray magnetic circular dichroism (XMCD) measurements clearly showed ferromagnetic ordering for Fe, Co, Ni, and ruled out ferromagnetic interactions for Mn and Cr, which was in contrast to MnCoNi alloy. Our studies thus highlight the element specific interactions strongly dependent on the composition and sample history providing an overview of magnetic properties of equiatomic MPEA systems.