Equilibrium shape equation and possible shapes of carbon nanotubes.

摘要: The structure and magnetic properties of SmMn2(Ge1-xSix)(2) compounds (x=0-1.0) have been investigated. All the crystallize in ThCr2Si2-type structure. Substitution Si for Ce leads to a linear decrease lattice constants unit-cell volume. In all transition from ferromagnetic antiferromagnetic state is observed at lower temperature T-1, which first decreases, goes through minimum x=0.4-0.6, then increases again with concentration. As increases, x<0.3 both antiferromagnetic-ferromagnetic ferromagnetic-paramagnetic transitions are as well T-2 Curie T-c, respectively. With increasing content T-c whereas 140 K x=0 215 x=0.2. For x greater than or equal 0.3 antiferromagnetic-paramagnetic was Neel content. saturation magnetization 1.5 decreases first, x=0.6, At room temperature, monotonically 3.27 mu(B)/f.u. nearly zero x=0.3. (C) 1996 American Institute Physics.