Atomic clusters and phase transitions in the metastable -Ta phase between andA. Arakcheeva and G. Chapuis
Ecole Polytechnique Fédérale de Lausanne, Institut de Physique de la Matière Complexe - BSP, 1015 Lausanne, Switzerland
received 19 July 2004; accepted in final form 19 November 2004
published online 5 January 2005
Atomic clusters were identified in the ground state of the non-equilibrium Ta phase (Frank-Kasper -structure type) at 15, 120 and 293 . The evolution of the clusters with temperature leads to two phase transformations at 65 and 150 which are related to the electrical and magnetic properties. The magnetic phase transition at 65 is associated with the magnetic symmetry group transformation P4'2/mn'm ( <65 ) to ( >65 ). It is shown that -U is also a two-component composite containing similar clusters. The nature of the stabilisation of -Ta at the cathode is discussed.
61.50.-f - Crystalline state.
61.66.Bi - Elemental solids.
64.60.My - Metastable phases.
© EDP Sciences 2005