Comparative Study of Irradiation-induced and Thermally Induced Structural Phase Transitions in Equilibrium Immiscible Fe–Ag Systems

Size-Dependent Phase Stability of Silver Nanocrystals

“…Recent researches show that a unique hexagonal 4H structural phase of Ag crystals (Ag-4H) with an abcbabcba ...-type of stacking sequence has been observed experimentally in the Ag nanoparticles, nanowires, and nanobelts. − This structure is different from the common face-centered-cubic (FCC) structure of Ag crystals (Ag-FCC) with an abcabca ...-type of stacking sequence in its bulk form. It is found that (1) Ag-4H and Ag-FCC could coexist at a particular condition and (2) the Ag-4H is the stable phase in Ag nanocrystals when their r remains smaller than a critical size r c at a certain temperature T . − Approaching r c , the Ag-4H and Ag-FCC reach an equilibrium, implying their difference in the Gibbs free energy Δ G ( r , T ) = G 4H ( r , T ) − G FCC ( r , T ) = 0, where G ( r , T ) is size- and temperature-dependent Gibbs free energy, and the superscripts 4H and FCC denote the Ag-4H and Ag-FCC, respectively. Note that r c is temperature-dependent and the corresponding r c ( T ) function has been the subject of experimental and theoretical investigations recently. ,− It is found that r c ( T ) progressively decreases with increasing T .…”

Size Effect on the Crystal Structure of Silver Nanowires

“…That is to say, no difference between the structures of the AgNWs and bulk silver was found. Only in silver nanoparticles, 4H structural silver, whose structure is different from that of the bulk silver, was reported. − …”