Spin correlations inZn1−cMncTealloys

Abstract

The nature of the spin correlations in ${\mathrm{Zn}}_{1-c}{\mathrm{Mn}}_c\mathrm{Te}$ alloys for three compositions has been investigated by neutron powder diffraction methods as a function of temperature $T$ between 300 and 2 K. The correlations, weak but observable at low $c$ and high $T$, intensify progressively as $c$ increases or $T$, decreases, but our experiments provide no clear evidence of a phase transition to a fully ordered magnetic structure. However, the appearance of broad, intense magnetic diffuse scattering peaks near positions that could be indexed as (1, ½,0), (1, $\frac{3}{2}$, 0), and (2,½,1) indicates a strong tendency towards the ordering of a type III antiferromagnet. The results are analyzed in terms of a theory of magnetic scattering from magnetic ions surrounded by near-neighbor shells of correlated spins.