Study of structural order–disorder thermal dependence dielectric properties for PbHPO4 and PbHAsO4 crystalsMuzaffar Iqbal Khan and Trilok Chandra UpadhyayEur. Phys. J. D, 75 5 (2021) 156DOI: https://doi.org/10.1140/epjd/s10053-021-00171-y