Generalized Mittag-Leffler relaxation of NH4H2PO4: Porous glass composite

► In this paper relaxation response of ammonium dihydrogen phosphate NH4H2PO4: porous glass composite was studied by means of impedance spectroscopy. ► It was found that the investigated material exhibits the two-power-law relaxation pattern with the low- (m) and high-frequency (n-1) exponents satisfying the relation m < 1 − n, where 0 < m, n < 1. ► We proposed relaxation scenario leading to the generalized Mittag-Leffler relaxation function, which gives insight into the microscopic origins of the power laws found experimentally.