The magnetostriction of solids is a key thermodynamic property that reflects essential interactions between correlated electron systems and the underlying crystal lattice. In particular, measurements at ultra-low temperatures and in very high pulsed magnetic fields are of significant relevance to track smallest magnetic interactions in superconductors, quantum materials, semiconductors or insulators. I will provide a summary of possible experimental setups and methods, including those with future application potential.
Measurements on the spin liquid delafossite NaGdS2, that undergoes a magnetic transition at about 180 mK, and the magnetoelastic characterization of topological skyrmion structures in Gd3Ru4Al12 are examples of experiments down to the milliklevin range in moderate static fields. As these static fields increase to approximately 40 T, magnetoelastic quantum oscillations can be detected, for example, to analyze the pressure dependence of the Fermi surface of Pd.
The optical Fiber Bragg Grating (FBG) method was developed to prevent interference effects (mechanical or electromagnetic noise, eddy current heating) in pulsed magnetic fields up to or even exceeding 100 T. This is illustrated by measured data leading to microscopic spin states of LaCoO3, later continued at ISSP Tokyo, and the analysis oft the phase diagram of SrFeO3. All these examples underscore the physical significance of magnetostriction in combination with other microscopic or spectroscopic methods.
A short introduction to the theoretical description of magnetoelastic effects using mean-field theory concludes the presentation.