Rietveld Refinement Study of GeSb2Te4 Bulks Prepared Through Distinct Melting Profiles. (2017)

• Record Type: Journal Article
• Authors: Kaur, Jashangeet; Tripathi, S.K; Ankush, ; Sharma, Manish Dev; Kanika, ; Goyal, Navdeep
• Is Part Of: Materials today. Volume 4:Number 9(2017)
• Page Start: 9524
• Page End: 9528
• Publication Date: 2017
• Subjects: GeSbTe -- Rietveld Refinement -- PANalytical X'pert Highscore Plus -- Melt-Quench; Materials science -- Congresses -- Periodicals; 620.1
• DOI: 10.1016/j.matpr.2017.06.217
• Languages: English
• ISSNs: 2214-7853

Abstract

Abstract: Quench and melt growth is an utmost pertinent and commercial method for bulk material formation because of the large flexibility in compositions accomplished through it. A slight modification in the conventional procedure was examined with two distinct temperature profiles i.e ramp annealing and step annealing to assist the process of continuous hardening of the melt. Ramp annealing is an isothermal heating process for several hours at the temperature of 1000°C whereas step annealing involves three halts of specific time period which is determined by the melting points of constituent elements. The polycrystalline bulks of Ge1 Sb2 Te4 were prepared with above mentioned procedures and characterized with powder X-ray diffraction technique. The influence of these temperature profiles was analyzed with the help of three modules contained in PANalytical X'pert Highscore Plus (PXHP) software. Firstly, the measured profiles were compared with a standard data (JCPDS card no. 01-089-1064 [1]) by Rietveld Refinement and a better goodness of fit was obtained in the case of step annealed samples. Secondly, Williamson-Hall plot, constructed between βcosθ and sinθ, linearly fits the statistics of multiple peaks. The slope of this line reveals the value of micro-strain and the intercept is used to calculate the crystallite size [2]. Lastly, the precise variation of peak width with 2theta is illustrated in virtue of FWHM/Halfwidth plot which highlights the trend in lattice parameters. The step annealing profile ensures a better homogeneity of the mixture and consequently a higher understanding of this method can pave a preferable way of obtaining bulk samples.