In this article, we introduce our recent works of x-ray fluorescence holography (XFH) to investigate atomic configurations in some functional materials, such as Zn_1−xMn_xTe diluted magnetic semiconductor and Ge_1−xMn_xTe high-temperature ferromagnetic thin films. From these experiments, we found that diffraction methods reflecting long-range periodicity have a crucial disadvantage in studying local-and intermediate-range atomic configurations, which are very important to determine physical properties of these materials. We present new aspects on the local structures of these materials by our XFH experiments and their analyses.