Magnetic and thermodynamic studies of new lamellar structure Mn0.5Co0.5NH4PO4 center dot 2H(2)O

Mn0.5Co0.5NH4PO4. 2H(2)O has been synthesized at room temperature by coprecipitation method. The structure was determined on X-ray powder diffraction data leading to a crystallization in the space group Pmn2(1) with cell parameters a = 5.568 +/- 0.011 angstrom, b = 6.158 +/- 0.008 angstrom and c = 19.38 +/- 0.04 angstrom. TG-DTA curves, suggest the loss of water hydration (2 H2O).The IR spectrum is characteristic of H2O, PO43- and NH4+ radicals. The magnetic study confirms the presence of two ions Co2+ and Mn2+ with ratio 1/2-1/2 and exhibits an antiferromagnetic comportment.