Size dependence of phase transition temperatures of ferromagnetic, ferroelectric and superconductive nanocrystals

摘要: With the miniaturization of devices, size and interface effects become increasingly important for properties performances nanomaterials. Here, we present a thermodynamic approach to mechanism behind size-induced unusual behavior in phase stabilities ferromagnetic (FM), antiferromagnetic (AFM), ferroelectric (FE), superconductive (SC) nanocrystals, which are different dramatically from their bulk counterparts. This method is based on Lindemann criterion melting, Mott’s expression vibrational melting entropy, Shi model size-dependent temperature. Simple unified functions, without any adjustable parameter, established dependences thermal FM, AFM, FE SC nanocrystals. According these analytic as nanocrystals reduced, may strengthen or weaken, depending confluence surface/volume ratio FM(AFM, SC)/substrate situations. The validity this confirmed by large number experimental results. theory will be significant choice materials design devices practical application.