The Role of Re in the Magnetic Properties of U(Fe1−xRex)2
UFe2, UCo2 (both MgCu2-structure) and UNi2(MgZn2-structure) form a very interesting class of U-based alloys in which a cross-over takes place from 3d-ferromagnetism (in UFe2) to 5f-ferromagnetism (in UNi2) via an enhanced Pauli paramagnet (UCo2). The U-U distance in these materials is 3.05 A, 3.03 A and 3.00 A, respectively, and is much smaller than the Hill limit (3.5A). The reduction of magnetic moment on Fe atoms in UFe2, as compared to that, for instance, in TbFe2 and ErFe2, is attributed to the electron transfer from the uranium atoms to iron atoms . The magnetic moment per unit cell, as well as the ferromagnetic transition temperature, Tc, decreases rapidly as a function of x in the pseudo-binary system U(Fe1−xCox)2 . The 3d magnetic instability gets suppressed with increasing amount of charge transfer from Co-atoms to the 3d-band of iron resulting in a reduction of magnetic moment on iron atoms. This is in contrast with the situation in U(Ni1−xCux)2 where introduction of Cuimpurity enhances the magnetic moment of U-atoms and the ordering temperature . Our recent Mossbauer investigations on U(Fe1−xCox)2 (x = 0.08 and 0.20) showed that the moment on iron atoms as obtained from Mossbauer studies is systematically lower than that obtained from magnetic studies, under the assumption that U and Co atoms carry no magnetic moment . It is, therefore, considered to be of interest to examine how the magnetic moment on Fe in UFe2 would behave if Fe is partially replaced by transition metal atoms on the right and left of Fe in the Periodic Table. In this paper we report our investigations on magnetic properties of U(Fe1−xRex)2
KeywordsIron Atom Transition Metal Atom Uranium Atom Saturation Magnetic Moment Small Magnetic Moment
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