NEUTRON-DIFFRACTION STUDIES OF ZINCBLENDE MNTE EPITAXIAL-FILMS AND MNTE ZNTE SUPERLATTICES - THE EFFECT OF STRAIN AND DILUTION ON A STRONGLY FRUSTRATED FCC ANTIFERROMAGNET/
Tm. Giebultowicz et al., NEUTRON-DIFFRACTION STUDIES OF ZINCBLENDE MNTE EPITAXIAL-FILMS AND MNTE ZNTE SUPERLATTICES - THE EFFECT OF STRAIN AND DILUTION ON A STRONGLY FRUSTRATED FCC ANTIFERROMAGNET/, Physical review. B, Condensed matter, 48(17), 1993, pp. 12817-12833
We report neutron-diffraction studies of antiferromagnetism in various
forms of epitaxially grown zinc-blende (ZB) MnTe: in semibulk (approx
imately 1 mum thick) single-crystal films of pure MnTe, in its magneti
cally diluted derivative Zn1-xMnxTe with 0.695 < x < 1, and in strongl
y strained very thin (30-300 angstrom) single-crystal MnTe layers in M
nTe/ZnTe superlattices. ZB Mn chalcogenides are unique examples of fcc
Heisenberg antiferromagnets (AF) with dominant nearest-neighbor inter
actions. Such a lattice is one of the basic models of topologically fr
ustrated spin systems. Only ZB MnS can be obtained through natural cry
stallization (and only in a fine powder form, which seriously limits t
he scope of possible studies on this system). The single-crystal forms
of MnTe obtained using molecular-beam epitaxy have made it possible t
o study the influence of strain on a frustrated fcc antiferromagnet. W
e observe that such built-in strain strongly affects the domain struct
ure as well as the phase-transition behavior. Furthermore, high-resolu
tion x-ray diffraction reveals pronounced magnetostriction effects in
the MnTe films. Both neutron as well as x-ray data indicate a rather u
nusual effect of a strong temperature shift in the relative population
s of two inequivalent AF domain states, and a magnetosctriction mechan
ism underlying this phenomenon is proposed. Finally, the data obtained
on Zn1-xMnxTe films complement the results of previous magnetic studi
es on bulk forms of this material with x less-than-or-equal-to 0.68.