Phase Transitions in Fe(x)S(x = 0.90--1.00) Studied by Neutron Diffraction.

Magnetic Phase Relations of Pyrrhotite

“…Phase Relations of Pyrrhotite thermal hysteresis on the low temperature side and is ascribed to an antif erromagnetic-f errimagnetic transition associated with a change in the vacancy ordering pattern (HIRONE et al ., 1954b;LOTGERING, 1956;ANDRESEN and TORBO, 1967). The disappearance at higher temperatures of the additional magnetization represented by this peak is entirely reversible and suggests a Curie temperature .…”

“…Microprobe data are given in Table 1. ANDRESEN and TORBO, 1967). The curve depicted in Fig, lb shows a normal gradual decrease of the magnetization during heating with a single curves shown in Fig.…”

Mössbauer and magnetic study of the antiferro to ferrimagnetic phase transition in Fe9S10 and the magnetokinetics of the diffusion of iron atoms during the transition

“…The antiferromagnetic to ferrimagnetic phase transition referred to as the A transition in the cation deficient iron sulfide FegSlO has been studied by several workers [1][2][3][4][5][6]. Typical results obtained in our laboratory for the magnetization as a function of increasing temperature are shown in Fig.…”

Mo¨ssbauer study of iron sulfides doped with 3d-transition metals

“…Magnetic-susceptibility and neutron-diffraction measurements [2][3][4] show that the FeS is antiferromagnetic with a Néel temperature of about 600 K and that the spin direction changes from perpendicular to parallel with the c axis below T a .…”

“…In the neighborhood of T a y400 K, a crystallographic phase transition appears, usually called the a transition. Bertaut [1] has shown that FeS exists with a hexagonal NiAs structure above T a and transforms below T a to a hexagonal superstructure having a unit cell six times as large in volume as that of the NiAs structure above T a .Magnetic-susceptibility and neutron-diffraction measurements [2][3][4] show that the FeS is antiferromagnetic with a Néel temperature of about 600 K and that the spin direction changes from perpendicular to parallel with the c axis below T a .However, Sparks, Mead, and Komoto [3] demonstrated through more accurate neutron-diffraction measurements that for Fe 0.996 S the spin-rotation transition (the Morin transition) takes place at a temperature T M higher by 31 K than T a . Similar independence of the Morin and a transitions was reported by Thiel and van den Berg [5] using Mössbauer measurements for Fe 0.996 S, though they found that T M was lower by 28 K than T a in contrast to the other results [6][7][8].…”