Probing the Structural Order of Half-Heusler Phases in Sb-Doped (Ti,Zr,Hf)NiSn Thermoelectrics

The nanostructural features of a mechanically alloyed Sb-doped (Ti<sub>0.4</sub>Zr<sub>0.6</sub>)<sub>0.7</sub>Hf<sub>0.3</sub>NiSn thermoelectric (TE) Half-Heusler (HH) compound were addressed using Transmission Electron Microscopy (TEM) coupled with...

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Main Authors: Fani Pinakidou, Andreas Delimitis, Maria Katsikini
Format: Article
Language:English
Published: MDPI AG 2025-07-01
Series:Nanomaterials
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Online Access:https://www.mdpi.com/2079-4991/15/13/1037
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author Fani Pinakidou
Andreas Delimitis
Maria Katsikini
author_facet Fani Pinakidou
Andreas Delimitis
Maria Katsikini
author_sort Fani Pinakidou
collection DOAJ
description The nanostructural features of a mechanically alloyed Sb-doped (Ti<sub>0.4</sub>Zr<sub>0.6</sub>)<sub>0.7</sub>Hf<sub>0.3</sub>NiSn thermoelectric (TE) Half-Heusler (HH) compound were addressed using Transmission Electron Microscopy (TEM) coupled with Energy Dispersive Spectroscopy measurements and Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy. The EXAFS measurements at the Ni-<i>K</i>, Sn-<i>K,</i> Zr-<i>K,</i> and Hf-<i>L</i><sub>3</sub>-edge were implemented in an effort to reveal the influence of Hf and Zr incorporation into the crystal with respect to their previously measured TE properties. The substitution of Ti by Hf and Zr is expected to yield local lattice distortions due to the different atomic sizes of the dopants or/and electronic charge redistribution amongst the cations. However, the material is characterised by a high degree of crystallinity in both the short and long-range order, on average, and the nominal stoichiometry is identified as (Zr<sub>0.42</sub>Hf<sub>0.30</sub>Ti<sub>0.28</sub>)NiSn<sub>0.98</sub>Sb<sub>0.02</sub>. The synergistic effect of minimization of extended structural defects or lattice distortions and considerable alloying-induced point defect population contributes to the improved TE properties and leads to the previously reported enhancement of the figure of merit of the mixed HHs.
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spelling doaj-art-0d035fc325f34cc3a1a86711b4cc64a02025-08-20T03:50:21ZengMDPI AGNanomaterials2079-49912025-07-011513103710.3390/nano15131037Probing the Structural Order of Half-Heusler Phases in Sb-Doped (Ti,Zr,Hf)NiSn ThermoelectricsFani Pinakidou0Andreas Delimitis1Maria Katsikini2Department of Physics, Aristotle University of Thessaloniki, GR-54124 Thessaloniki, GreeceDepartment of Physics, Aristotle University of Thessaloniki, GR-54124 Thessaloniki, GreeceDepartment of Physics, Aristotle University of Thessaloniki, GR-54124 Thessaloniki, GreeceThe nanostructural features of a mechanically alloyed Sb-doped (Ti<sub>0.4</sub>Zr<sub>0.6</sub>)<sub>0.7</sub>Hf<sub>0.3</sub>NiSn thermoelectric (TE) Half-Heusler (HH) compound were addressed using Transmission Electron Microscopy (TEM) coupled with Energy Dispersive Spectroscopy measurements and Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy. The EXAFS measurements at the Ni-<i>K</i>, Sn-<i>K,</i> Zr-<i>K,</i> and Hf-<i>L</i><sub>3</sub>-edge were implemented in an effort to reveal the influence of Hf and Zr incorporation into the crystal with respect to their previously measured TE properties. The substitution of Ti by Hf and Zr is expected to yield local lattice distortions due to the different atomic sizes of the dopants or/and electronic charge redistribution amongst the cations. However, the material is characterised by a high degree of crystallinity in both the short and long-range order, on average, and the nominal stoichiometry is identified as (Zr<sub>0.42</sub>Hf<sub>0.30</sub>Ti<sub>0.28</sub>)NiSn<sub>0.98</sub>Sb<sub>0.02</sub>. The synergistic effect of minimization of extended structural defects or lattice distortions and considerable alloying-induced point defect population contributes to the improved TE properties and leads to the previously reported enhancement of the figure of merit of the mixed HHs.https://www.mdpi.com/2079-4991/15/13/1037Half-Heusler (HH)thermoelectrics (TEs)nanostructureExtended X-ray Absorption Fine Structure Spectroscopy (EXAFS)Transmission Electron Microscopy (TEM/HRTEM)Energy Dispersive X-ray Spectroscopy (EDS)
spellingShingle Fani Pinakidou
Andreas Delimitis
Maria Katsikini
Probing the Structural Order of Half-Heusler Phases in Sb-Doped (Ti,Zr,Hf)NiSn Thermoelectrics
Nanomaterials
Half-Heusler (HH)
thermoelectrics (TEs)
nanostructure
Extended X-ray Absorption Fine Structure Spectroscopy (EXAFS)
Transmission Electron Microscopy (TEM/HRTEM)
Energy Dispersive X-ray Spectroscopy (EDS)
title Probing the Structural Order of Half-Heusler Phases in Sb-Doped (Ti,Zr,Hf)NiSn Thermoelectrics
title_full Probing the Structural Order of Half-Heusler Phases in Sb-Doped (Ti,Zr,Hf)NiSn Thermoelectrics
title_fullStr Probing the Structural Order of Half-Heusler Phases in Sb-Doped (Ti,Zr,Hf)NiSn Thermoelectrics
title_full_unstemmed Probing the Structural Order of Half-Heusler Phases in Sb-Doped (Ti,Zr,Hf)NiSn Thermoelectrics
title_short Probing the Structural Order of Half-Heusler Phases in Sb-Doped (Ti,Zr,Hf)NiSn Thermoelectrics
title_sort probing the structural order of half heusler phases in sb doped ti zr hf nisn thermoelectrics
topic Half-Heusler (HH)
thermoelectrics (TEs)
nanostructure
Extended X-ray Absorption Fine Structure Spectroscopy (EXAFS)
Transmission Electron Microscopy (TEM/HRTEM)
Energy Dispersive X-ray Spectroscopy (EDS)
url https://www.mdpi.com/2079-4991/15/13/1037
work_keys_str_mv AT fanipinakidou probingthestructuralorderofhalfheuslerphasesinsbdopedtizrhfnisnthermoelectrics
AT andreasdelimitis probingthestructuralorderofhalfheuslerphasesinsbdopedtizrhfnisnthermoelectrics
AT mariakatsikini probingthestructuralorderofhalfheuslerphasesinsbdopedtizrhfnisnthermoelectrics