The origin of the Invar effect, whereby certain ferromagnetic alloys exhibit near zero thermal expansion around room temperature is still not properly understood. Although the phenomenological two state model proposed by Wiess, where thermal population between two different spin states of high and low volumes can be used to explain the curious thermal expansion, there has been no direct observation to corroborate the theory. Recently many studies have involved the use of electronic structure calculations using many different techniques, many of which infer that disorder, either in the magnitude of the local moments, or in the degree of collinearity plays a role in the phenomena observed in these systems. The aim of the proposed experiment is to use a local probe of the magnetism to provide complementary data that can be compared with the predictions of such theoretical investigations.