The Magnetic Properties of the Alloys Fe (A1,Mn) System

The Magnetic Properties of the Alloys Fe (A1,Mn) System

Zajel / An-Najah National University

Sabri Ahmed Al-Tannah In this thesis we study the magnetic properties of the alloy system Fe (All, Mn), for x=0.31, 0.35,          0.60 and 0.80, by measuring the susceptibility in the temperature range 300< T < 650 K° in very small ac magnetic field. The analysis of the susceptibility curves show that the sample with x=0.31 is paramagnetic, while the samples with x=0.35, 0.60 and 0.80 are ferromagnetically ordered. The susceptibility for x=0.31 obeys the Curie-Weiss law with a negative paramagnetic temperature (9p= -144K) and shows nearly a straight line with nearly the same susceptibility during all the process. For the other samples (with x=0.35, 0.60 and 0.80) show the coexistence of ferromagnetic and antiferromagnetic behavior with Neel temperature (TN) = 335, 387 and 393 K and with paramagnetic temperature ©p= 340,393 and 425 K respectively. It is clear that the sample with x=0.31 exhibits only one paramagnetic phase, but for the other samples, two phases exist; antiferromagnetic phase below Neel temperature and paramagnetic phase above Neel temperature. The Fe (All_gMng) alloy system is very sensitive to temperature and the measured values for both susceptibility and Neel temperature during heating do not coincide with those values during cooling. Sabri Ahmed Al-Tannah Supervisor Dr. M. Y. Seh May 2001