It can be observed from Figure 3a that atomic arrangement in the monolithic FeNi film has high periodicity,

indicating that the film is well crystallized. The SAED pattern in Figure 3d shows that the monolithic FeNi film only exhibits a fcc structure, which is consistent with the XRD result. From Figure 3b, it can be seen that the dark and bright layers, corresponding to FeNi and V, respectively, are about 10 and 1.5 nm, which are consistent with the structure design. As the V layers with the thickness of 1.5 nm are inserted in the FeNi film, the lattice fringes continuously go through several layers and interfaces, VS-4718 supplier indicating that V layers have not existed in a bcc structure, but transformed to a fcc structure and grown epitaxially with FeNi layers, which validates the above deduction from the XRD results. From the SAED pattern in Figure 3e, the film is composed of both

fcc and bcc structures. According to the above analysis and XRD results, the bcc-structured phase corresponds to FeNi, rather than V. Therefore, it can be reasonably believed that the martensitic transformation occurs in the FeNi layers of the FeNi/V nanomultilayered film under the epitaxial growth structure between FeNi and V layers. As the V layer thickness increases to 2.0 nm, however, V layers cannot maintain the epitaxial growth with FeNi layers, but present an amorphous state, as shown in Figure 3c. The lattice fringes in FeNi layers cannot traverse through the V layers, manifesting the epitaxial growth structure is blocked by the V layers. The SAED pattern in Figure 3f see more indicates that only a fcc structure exists within the film, suggesting that martensitic transformation in FeNi layers terminates, Loperamide which agrees with the XRD results. Figure 3 Cross-sectional HRTEM images and selected area electron diffraction (SAED) patterns. (a, d) Monolithic FeNi film and FeNi/V nanomultilayered films with V layer thicknesses of (b, e) 1.5 nm and (c, f) 2.0 nm. It is worth noting that the diffraction information

of V layers is not detected in the SAED patterns for the FeNi/V nanomultilayered films with different V layer thicknesses in Figure 3, which can be attributed to two aspects. Firstly, when V layers grow epitaxially with FeNi layers, V layers transform into a fcc structure under the template effect of FeNi layers, and the lattice parameter is inclined to increase and approach that of FeNi. Therefore, the SAED rings of V may coincide with those of FeNi. A similar phenomenon could also be found in our recent investigation of CrAlN/ZrO2 nanomultilayered films [21]. When the thickness of the ZrO2 layer was less than 1.0 nm, the originally tetragonal-structured ZrO2 layers were forced to transform to a pseudomorphic fcc structure and grew epitaxially with CrAlN layers. In this case, the SAED patterns can be only composed of a fcc structure, without detection of a tetragonal structure. Secondly, as the V layer thickness increases to 2.