A magneto-elastic transition that occurs in quasi one-dimensional antiferromagnetic
materials when the magnetic
free energy decrease due to the formation of singlet spin pairs outweighs the increase in lattice
free energy occurring as a result of the
dimerization of the regular array. Example: The transition in tetrathiafulvalenium bis(dithiolene)cuprate
at
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.
Source:
PAC, 1994, 66, 577
(Definitions of terms relating to phase transitions of the solid state (IUPAC Recommendations
1994))
on page 591