REENTRANT SPIN-GLASS-LIKE BEHAVIOR OF (FE0.90CR0.05NI0.05)2P

Di-iron phosphide with small substitutions of iron with Cr and Ni, (Fe 0.90Cr0.05Ni0.05)2P, has been investigated by SQUID-magnetometry. The sample exhibits a first order ferromagnetic transition at T(c) almost- equal-to 180 K and a re-entrant spin glass transition at T(g) almost-e qual-to 125 K. The ferromagnetic transition is severely smeared by wea k applied magnetic fields. The re-entrant transition is evidenced from both dc-magnetisation and ac-susceptibility measurements. An aging ph enomenon is observed at temperatures below T(g) and the freezing tempe ratures, T(f), and their corresponding relaxation times, tau scale acc ording to conventional critical slowing down: tau/tau0 = ((T(f) - T(g) )/T(g))-znu, with an exponent znu almost-equal-to 9, a value that is f ound also at ordinary paramagnetic to spin glass transitions.