Channeling study of melting and solidification of lead nanocrystals in aluminium

Extreme lowering of the Debye temperature of Sn nanoclusters embedded in thermally grownSiO2by low-lying vibrational surface modes

“…A strong decrease of the melting temperature of nanocrystalline ␤-Sn has already been predicted and measured by several authors. [30][31][32][33][34] A lowering of the melting temperature by more than 100 K has been measured on very small isolated Sn clusters ͑N ϳ 500͒ (Ref. 31) while even bigger reductions are predicted by thermodynamical models.…”

Amorphization of Ge nanocrystals embedded in amorphous silica under ion irradiation

“…In previous studies, it has been shown that the properties of nanocrystals may significantly vary from the properties of the same crystals in the bulk phase. For instance, the melting point of crystal structure of the nanosize can be significantly higher or lower than that of the same element or compound in its conventional phase depending on the nature of surrounding matter [4][5][6][7][8][9][10][11]. High-dose ion irradiation of elemental metal nanoclusters leads to the amorphization of their crystal structure, while it is known that elemental bulk metals can not be amorphized [12].…”

Partial melting mechanisms of embedded nanocrystals

“…This could specifically be the case in transmissionelectron microscopy ͑real-space images͒ 4,52 and Rutherford backscattering/channeling experiment. 8,11,14,54 On the other hand, methods which measure the average atomic shortrange order such as Raman and certain x-ray approaches 14,56 would be expected to interpret nanocrystals to still remain crystalline during the defect motion state.…”

“…2,3 While nanoclusters in vacuum are well known to usually melt at temperatures much below the normal bulk melting point 1,4 ͑with the exception of some very small systems with only a few tens of atoms 5,6 ͒, embedded nanoclusters have been variously reported to melt below or above the bulk melting temperature. 4,[7][8][9][10][11][12][13][14][15][16][17][18][19][20] Perhaps the most intriguing is the experimental 4 and computational evidence 21 of embedded or coated nanoclusters which shows that even in the same system, the melting point can be either lowered or increased depending on the nature of the interface. Several different theoretical models have been proposed to explain the melting mechanisms in embedded nanoclusters but it is not clear which, if any, of them has general validity ͑for a recent review see Ref.…”