Intensity of each peak in XRD pattern depends on 6 factors including Structure-factor, Multiplicity, Lorentz, Polarization,  Absorption, and Temperature factor. The first four factors play an important role in intensity of peaks. "ELEMENTS OF X-RAY DIFFRACTION" by B. D. CULLITY is quite instructive in this issue.

I hope Cullity is not using the term spectrum for a diffractogram in his book. And one shouldn't underestimate texture which affects the multiplicity remarkably. In fact, all factors are very important including absorption (for mixtures) and temperature which also "considers" somehow lattice defects.

Dear colleague Nita Ghosh,

Have a nice time and good day.

The high intensity XDR peak always has low value of full width half maximum, FWHM which meant high crystallite size and the low value  intensity XDR peak  has high value of FWHM. The low values FWHM (high intensity) has crystallite with sizes higher than the low values of FWHM. So you have two preferred orientations; the first one at 27.4 degree (high intensity- low FWHM) and characterized by high size of crystallites, the second preferred orientation at 13.1 degree  (low intensity- high FWHM) and characterized by low size of crystallites, The high order material has low FWHM and high intensity and vise versa.

I wish this is useful and help you.

Yours

A. EL-Denglawey

Cullity uses the term “diffraction patterns”. He distinguishes between spectrometers that use a crystal of known structure to measure X-ray spectra and diffractometers that determine crystal structure by diffraction using a known wavelength.

ERADICATE the term 'spectrum' from XRD!!

Diffraction is not a spectroscopic technique. Therefore, please avoid phrases such as XRD Spectrum, X-Ray spectrum or X-Ray Diffraction Spectrum and use XRD Pattern, X-Ray Diffraction Pattern or simply Diffractogram.

Multiplicity, Crystallite size, preferred orientation. By comparing values of Crystallite size and microstrain you can check if they have preferred orientation: the more different these values, higher is this preferred orientation. In addition, check the peak's multiplicity, as such number is related to the intensity.