The microstructureofCaMnO3 nanofibers correspondingto
selected-areaelectrondiffraction(SAED)andEDXspectrumare
shown in Fig. 2e–f. Thebright field TEMimageshowedthatthe
CaMnO3 nanofibers wereactuallymadeupofseveralcrystalline
CaMnO3 grains withthegrainsizerangingfrom60to90nm,as
shown in Fig.2e. Anaverage fiber diameterof552nmwasob-
served fromtheTEMimage.TheSAEDpatternsareconsistentwith
the differentconcentricringsinordertoconfirm thepolycrystal-
line natureofthesamples.Thediffractionrings(Fig. 2f) indicated
that CaMnO3 had apolycrystallinestructurecorrespondingto
majorcrystalplanesofCaMnO3 phases, whichareconsistentwith
the XRDanalysis.TheEDXattachedtotheTEMwasusedto
measure theelementalcompositionanddistributionasshownin
Fig.2g. TheresultsshowedthatCaMnO3 nanofibers werecom-
posed mainlyofcalcium,manganese,andoxygen.TheEDXresults
showedthatnoimpuritiesweredetectedapartfromacarbonand
copper signalarisingfromthemeasurement.