J. Phys. France 43, 1365-1369 (1982)
DOI: 10.1051/jphys:019820043090136500

Phase diagram of antiferromagnetic CrFe in the pressure-temperature plane

E. Fawcett¹ et C. Vettier<sup>2

1</sup>  University of Toronto, Canada
²  Institut Laue-Langevin, 156 X, 38042 Grenoble Cedex, France

Abstract
The phase diagram under pressure up to 4 kbar of an alloy containing 2.8 at % Fe in chromium has been determined by neutron diffraction. A hysteretic first order transition to a commensurate spin density wave phase, together with an apparently second order transition from the disordered paramagnetic phase to an incommensurate phase, is observed. No triple point could be found and there is little change in the incommensurability parameter as the commensurate phase is approached. The amplitude of the spin density wave decreases from the commensurate to the incommensurate phase by about a third.

Résumé
Le diagramme de phase d'un alliage CrFe (2,8 % at) a été obtenu par diffraction neutronique jusqu'à des pressions de 4 kbar. On a mis en évidence une transition du premier ordre avec hystéresis vers une phase antiferromagnétique commensurable; la transition entre les phases paramagnétique et incommensurable est du second ordre. Il n'y a pas de point triple et le vecteur de propagation de la phase incommensurable varie peu, même au voisinage de la phase commensurable. Cependant, l'amplitude de l'onde de densité de spin diminue de 30 % à la transition commensurable-incommensurable.

PACS
6250 - High-pressure and shock wave effects in solids and liquids.
6470K - Solid-solid transitions.
7525 - Spin arrangements in magnetically ordered materials (including neutron and spin-polarized electron studies, synchrotron-source x-ray scattering, etc.).
7530K - Magnetic phase boundaries (including magnetic transitions, metamagnetism, etc.).

Key words
antiferromagnetic properties of substances -- chromium alloys -- commensurate incommensurate transformations -- high pressure solid state phase transformations -- iron alloys -- magnetic transitions -- magnetomechanical effects -- neutron diffraction examination of materials -- phase diagrams -- spin density waves