The nematic-smectic-$A$ transition temperature of mixtures of HBAB {$p$-[($p$-hexyloxybenzylidene)-amino]benzonitrile} and CBOOA [N-$p$-cyanobenzylidene-$p-n$-octyloxyaniline] becomes multivalued with increasing concentration of HBAB. The nematic phase occurs at both a higher and a lower temperature than the smectic phase. Measurements of the bend elastic constant as a function of concentration are presented.

• Received 7 April 1975

DOI:https://doi.org/10.1103/PhysRevLett.35.48