Size induced large upward shift of magnetic transition temperatures in nanowires of rare-earth transition metal alloy GdxCo1-x(x=0.4)

It has been observed that in nanowires (diameter similar to 100 nm) of a rare-earth (RE) transition metal (TM) alloy GdxCa1-x(x = 0.4) the magnetic transition temperatures like the magnetization compensation temperatures (T-cm) can be shifted upward by nearly 350 K compared to that of the bulk and be made as high as 850 K. The saturation magnetization (M-S) remains high over the whole temperature range compared to that the bulk and at room temperature the enhancement in M-S is 33%. This enhances the applicability of the RE-TM alloy to well above the room temperature. The magnetic experiments were carried out in the temperature range 80 K-1100 K on the alloy nanowires grown by electrochemical synthesis in the nanopores of Anodic Aluminium Oxide (AAO) templates. It has been established that the large shift in the T-cm is linked to qualitative change in the nature of the anisotropy energy E-A on size reduction, in particular in the temperature derivative dE(A)/dT that reaches more or less temperature independent value in the nanowires. (C) 2018 Elsevier B.V. All rights reserved.