| Semi-metallic ferromagnets have special band structure,which makes them have a wide range of applications in spintronics devices.CrO2 as a very important semi-metallic ferromagnet has a spin polarization of nearly 100%on the Fermi plane.In addition,CrO2 has excellent electrical conductivity and high Curie temperature,making it an important material in the field of spintronics.However,because CrO2 is in thermodynamically metastable phase at atmospheric pressure,it is easy to decompose into more stable chromium oxide,which leads to the appearance of Cr in other valence states in the synthesis of thin film materials.To determine the presence of other Cr oxides in the grown film material,transmission electron microscopy was used to characterize CrO2 films grown using chemical vapor deposition(CVD).Transmission electron microscope(TEM)is a precise scientific instrument for imaging on the microscopic scale.It has been widely used in the fields of materials science,condensed matter physics,structural biology and so on.In recent decades,many important discoveries have been made using transmission electron microscopy.Transmission electron microscope uses electrons with a shorter wavelength as the wave source,and its resolution is much higher than that of optical microscope.Transmission electron microscope can also be used for crystal structure,element composition analysis and other aspects of the characterization.Transmission electron microscope(TEM)has attracted much attention for its powerful function since it was developed.The range of research is becoming wider and the resolution is gradually improving.In this paper,the growth,atomic structure and valence state of CrO2 thin films were studied by using transmission electron microscopy combined with selective electron diffraction,high resolution transmission electron microscopy,electron energy loss spectroscopy,scanning transmission electron microscopy and other analytical methods. |
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