MAGNETIC-BEHAVIOR OF (FE0.90CR0.03NI0.07)2P AND (FE0.90CR0.05NI0.05)2P

(Fe0.90Cr0.03Ni0.07)2P and (Fe0.90Cr0.05Ni0.05)2P are found to crystal lize in Fe2P-like hexagonal symmetry (hereafter referred to as FCN37 a nd FCN55, respectively). dc magnetization measurements have been made in external fields upto 8 kOe and in the temperature range 80-800 K. a c susceptibility measurements have been performed in the temperature r ange 80-300 K. dc measurements show that the two alloys are ferromagne tic with T(c) approximately 250 K for FCN37 and approximately 180 K fo r FCN55. Magnetic moments of the polycrystalline samples at 7 kOe and approximately 90 K are 67 and 47 emu/g for FCN37 and FCN55, respective ly. Both of them also exhibit small but finite remanence and coercivit y. The temperature dependent magnetization measurements made on FCN37 and FCN55 in zero field cooling and field cooling modes branch off at approximately 230 and approximately 125 K, respectively. Remanent magn etization, measured in the remanent field of the magnet (approximately 20 Oe), preceded by isothermal cooling of the samples down to 85 K an d applications of different fields for fixed interval, relaxes over a period of time following log t. Peak in the ac susceptibility-temperat ure curve, measured at three frequencies in the interval 27-983 Hz, sh ifts with frequency obeying Vogel-Fulcher law. Results suggest existen ce of magnetic clusters in the two ferromagnetically ordered alloys, o r spin glass state at low temperatures, or both.