Electronic diffusion and directional order in the magnetic semiconductor HgCr2Se4

The existence of a directional order has been shown in a HgCr
2
Se
4
single crystal reheated with Hg atmosphere, by measuring the magnetic aftereffect and the anisotropy. The directional order is attributed to an electron migration between Cr
²⁺
and Cr
³⁺
on B sites; the n-type carriers created by the thermal treatment with Hg are shown to be mostly due to the Cr
²⁺
ions formed during the treatment.