Amorphization of rare earth - cobalt intermetallic alloys by swift heavy-ion irradiation

Abstract

(R = Y, Ce and Tm) and ( R= Y and Ce) intermetallic compounds have been irradiated for the first time by swift heavy-ion beams (U, Pb) of energy 1 - 5 GeV at GANIL (Caen, France). The compounds , and are found to be partially amorphized after irradiation. The amorphized volume fraction has been determined as a function of the ion beam fluence by x-ray diffraction and magnetic measurements. Results are found to be in agreement. By means of a phenomenological model, associating the phenomena of amorphization and recrystallization, the diameters of the latent tracks are estimated to lie in the range 2 - 3 nm. In contrast, no amorphization is observed in and . The different behaviours observed are well understood, in the framework of the thermal spike model, in terms of the different values of the electron - phonon coupling constant of the irradiated compounds.

Magnetic behaviour of nanosized zinc ferrite under heavy ion irradiation

“…Presence of this ZnO phase and degradation of crystalline structure may give rise to decrease in magnetization as observed in our case (Fig. 3) at RT [24]. At 10 K the value of r s decreases slightly with fluence for system ZF500.…”

“…The apparent difference in the values of blocking temperature for pristine samples as shown in Table 1 may be attributed to the size effects [24,27]. The blocking temperature with fluence for the system ZF500 remains almost constant within experimental error.…”

Study of 130 Mev Ni Ion Irradiation Induced Surface Modification of DLC Films Grown By Microwave Plasma CVD.

“…The 130 MeV Ni ions predominantly lose their energy in the DLC material by electronic excitation where the energy of the ion is transferred to the lattice atoms through electron-phonon interactions [14]. The thermal energy developed in the lattice leads to the formation of nanodimensional defects in the lattice [14]. The conversion of DLC material from sp 3 to sp 2 in the track of the ions was also observed previously [15].…”

“…These results suggest increase of sp 2 bonding in the films [10] which can be due to the local heating caused by the 130 MeV Ni ions as they pass in the film. The 130 MeV Ni ions predominantly lose their energy in the DLC material by electronic excitation where the energy of the ion is transferred to the lattice atoms through electron-phonon interactions [14]. The thermal energy developed in the lattice leads to the formation of nanodimensional defects in the lattice [14].…”

Ion Species/Energy Dependence of Irradiation-Induced Lattice Structure Transformation and Surface Hardness of Ni₃Nb and Ni₃Ta Intermetallic Compounds

“…It has been reported so far that some intermetallic compounds such as NiZr 2 42) , RCo 2 and RCo 3 (R = rare earth elements) 43) , and NiTi 44) show lattice structure transformation through the high density electronic excitation. On the other hand, in the case of Ni 3 Nb and Ni 3 Ta, the present study shows that the energy deposited through the electronic excitation does little affect the lattice structure transformation.…”