I have been looking into magnetostriction, and I have found the measurement of the magnetostrictive strains is typically given as λ100, λ111 and λs.
My understanding is that these are the saturation strains measured along the relative crystal directions when a field is applied in that direction, for single crystal for the element or alloy.
And that λs is the saturation strain as a material moves from demagnetised to magnetised. And that 3/2λs is the total strain produced as the materials moves from its Curie temperature to fully magnetised in a single direction. Useful for poly-crystalline measurements of samples.
There is a material called Galfenol and one of the earliest papers that investigated the material and is often cited with references to the figure on the magnetostrictive measurements for the materials have the measurements with with the constants written as (3/2)λ100 and (3/2)λ111, and I am having trouble understanding why this is the case.