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From conventional alloys to HEA: grasp from magnetism and UPS

A change in properties on crossing from HEA to conventional alloy (CA) concentration range mirrors the corresponding change in electronic structure (ES) [1]. Here we present main results of an ongoing study of the evolution of ES and magnetism accompanying a transition from HEA to CA in crystalline (CrMnFeCo)1- xNix alloys [2] and amorphous (a-) (TiZrNbTL1)1- x(TL2)x (TL1=Cu or Ni, TL2=Ni [3], Cu or Co) alloys. Ultraviolet Photoemission Spectroscopy (UPS) showed split-band shape of the valence band of amorphous alloys with the electronic density of states around the Fermi level dominated with d-states of Ti, Zr and Nb, whereas the 3d-states of late transition metals were at higher binding energies. The amount of splitting depends strongly on particular 3d metal and to lesser extent on its content x. Change in properties on transition from CA to HEA depends strongly on amount of splitting [3]. In crystalline (CrMnFeCo)1-xNixalloys constituents form common band [1]. Our UPS study cannot provide full information about the band structure and magnetic state of these alloys. However, a comparison of measured spectra for selected alloys with the results of a-i calculations of the band structure [1] provides an insight into the evolution of ES with x. A study of the evolution of magnetism shows strong influence of inhomogeneity. [1] Sai Mu et al, npj Comp. Mat.5(2019)1 [2] M. Laurent-Brocq et al, Mat. Sci. Eng.A696(2017)228 [3] E. Babić et al, J Mat. Res. 33(2018)3170.

HIGH-ENTROPY ALLOYS ; ELECTRONIC-STRUCTURE ; MAGNETIC-SUSCEPTIBILITY

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