In my recent work, BT-based dielectric ceramic were characterized by ex situ XRD. The XRD pattern recorded at low temperature is beyond by expection. Till now, I can not match it with any JCPDS card. The XRD pattern and data are attached.
Dear Qilin,
in order to index this pattern, we need additional information about (a) the measurement conditions (X-ray source, optics (Bragg-Brentano focussing), detectors, scan (omega, theta-2theta, ...), etc, and (b) about your sample and its form, is it a powder, a film, a massive crystal, ...? Please specify, then we will see. Kind regards, Dirk
What about the temperature, as far as I know, BaTiO3 has at least 5 different polymorphs, especially they differ in the low temperature phases, i.e. they show two phase transitions between 15°C (ca. 280 K) and -80°C (ca. 190 K), from an ideal tetragonal phase via a orthorhombic phase for the intermediate temperatures to a rhomboedric structure at really low temperatures. So some additional input is needed ...Dirk
Hi, Dirk. it's true that BaTiO3 has at least 5 different polymorphs. At first, we also think the data may match with the low temperature phase of BaTiO3. But the result actually goes against our expection as we index the pattern using JADE software. Do your know any refercences or previous publications related to the phase tructure of BaTiO3 at low temperature?
It doesn't look like BaTiO3 at all. I attach an image from the PDF-2 of all five polymorphs.
One of the polymorphs has peaks below 20 degrees 2-theta so you might want to start at 10 or lower so you don't miss anything.
I tried to obtain an indexing from your data but there are no consistent results. I notice that you only have 124 counts in the main peak, the data are very poor and noisy, so this is going to cause problems.
Are you sure that the material is pure?
Ian, in fact this is similar to what I have simulated (with Powder cell and the 5 pdf-inputs). So I would agree with you conclusion, that there Quilin has no phase-pure material ... at least no BaTiO3 ;-(
Cheers, Dirk
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