Flower-like microparticles and novel superparamagnetic properties of new binary Co 1/2Fe 1/2(H 2PO 4) 2·2H 2O obtained by a rapid solid state route at ambient temperature

Abstract

A new binary Co 1/2Fe 1/2(H 2PO 4) 2·2H 2O was synthesized by a simple, rapid and cost-effective method using CoCO 3–Fe(c)–H 3PO 4 system at ambient temperature. Thermal treatment of the obtained Co 1/2Fe 1/2(H 2PO 4) 2·2H 2O at 600 °C yielded as a binary cobalt iron cyclotetraphosphate CoFeP 4O 12. The FTIR and XRD results of the synthesized Co 1/2Fe 1/2(H 2PO 4) 2·2H 2O and its final decomposed product CoFeP 4O 12 indicate the monoclinic phases with space group P2 1/ n and C2/ c, respectively. The particle morphologies of both binary metal compounds appear the flower-like microparticle shapes. Room temperature magnetization results show novel superparamagnetic behaviors of the Co 1/2Fe 1/2(H 2PO 4) 2·2H 2O and its final decomposed product CoFeP 4O 12, having no hysteresis loops in the range of ±10,000 Oe with the specific magnetization values of 0.045 and 12.502 emu/g at 10 kOe, respectively. The dominant physical properties of the obtained binary metal compounds (Co 1/2Fe 1/2(H 2PO 4) 2·2H 2O and CoFeP 4O 12) are compared with the single compounds (M(H 2PO 4) 2·2H 2O and M 2P 4O 12; where M = Co, Fe), indicating the presence of Co ions in substitution position of Fe ions.