Dear Mahanty, Thank you for your information. My material is Beta- NaGdF4 nanoparticle. I characterized with powder XRD. There are no impurity peaks. All patterns exactly matches with the reference one.
You could calibrate the TEM using an aluminum TEM grid (or any SAED calibration standard). This enables you to convert the pixel units on the image to an equivalent d-spacing. The equation to use is:
R*d = lambda*L (Camera constant)
Here R is the diameter of the ring on the SAED pattern, d is the d-spacing lambda is the wavelength and L is the camera length.
The camera constant has units of pixel-A, and can be used to obtain the d spacing (real space) once the SAED radius (k-space) is known. The d-spacing can then be compared with your XRD data for the nanoparticle.