Adaptable thermochromism in the Cu[Mo.sub.1-x][W.sub.x][O.sub.4] series (0(less than or equal to)X<0.1): a behavior related to a first-order phase transition with a transition temperature depending on X

Calorimetry, reflectivity and magnetism techniques were used for analyzing the transition temperature modifications with tungsten substitution. Findings reveal a significant increase in the temperature transition in a parallel way for the heating and cooling mode on substitution of molybdenum for tungsten.