Magnetoelastic Phase Transitions and Critical Behaviour of (Fe1-xNix)2P System
B. Średniawaa, R. Duraja, A. Pacynab, A. Bombikc, R. Zacha, M. Bacmannd, D. Fruchartd, S. Niziołc, P. Fornala and J. Staneke
a Institute of Physics, Technical University of Cracow, Podchorążych 1, 30-084 Cracow, Poland
b IFJ, Radzikowskiego 152, 31-342 Cracow, Poland
c WFiTJ, AGH, Al. Mickiewicza 30, 30-059 Cracow, Poland
d Lab. Cristallographie, CNRS, BP 166X, Av. Martyrs, Grenoble, France
e IF UJ, Reymonta 4, 30-059 Cracow, Poland
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This report focuses on magnetoelastic properties and critical behaviour of (Fe1-xNix)2P system. For low Ni content (x=0.01) an isolated critical point was found. Analysis of this critical behaviour in the frame of molecular field approximation was carried out. Moreover, thermal variations of the lattice parameters, as measured by X-ray diffraction techniques, were studied. The (P,T) phase diagrams obtained for several Ni contents show the evidence that the Curie temperature decreases with pressure. The Mössbauer spectra collected for x = 0.025, 0.1, 0.2, 0.25 at different temperatures are also analysed. The existence of two nonequivalent crystallographic sites occupied by iron atoms as well as local magnetic structure is discussed.
DOI: 10.12693/APhysPolA.97.921
PACS numbers: 75.50.Cc, 71.20.Lp