@article {1421,
	title = {Enhancing thermoelectric properties through control of Nickel Interstitials and phase separation in Heusler/Half-Heusler TiNi1.1Sn composites},
	journal = {Materials},
	volume = {11},
	year = {2018},
	pages = {1{\textendash}12},
	abstract = {<p>
	Thermoelectric devices, which allow direct conversion of heat into electrical energy, require materials with improved figures of merit (zT) in order to ensure widespread adoption. Several techniques have been proposed to increase the zT of known thermoelectric materials through the reduction of thermal conductivity, including heavy atom substitution, grain size reduction and inclusion of a semicoherent second phase. The goal in these approaches is to reduce thermal conductivity through phonon scattering without modifying the electronic properties. In this work, we demonstrate that Ni interstitials in the half-Heusler thermoelectric TiNiSn can be created and controlled in order to improve physical properties. Ni interstitials in TiNi1.1Sn are not thermodynamically stable and, instead, are kinetically trapped using appropriate heat treatments. The Ni interstitials, which act as point defect phonon scattering centers and modify the electronic states near the Fermi level, result in reduced thermal conductivity and enhance the Seebeck coefficient. The best materials tested here, created from controlled heat treatments of TiNi1.1Sn samples, display zT = 0.26 at 300 K, the largest value reported for compounds in the Ti-Ni-Sn family.
</p>
},
	keywords = {Heusler, Phonon scattering, Point defect, Thermoelectric, TiNi2Sn, TiNiSn},
	issn = {19961944},
	doi = {10.3390/ma11060903},
	author = {Levin, Emily E. and Long, Francesca and Douglas, Jason E. and Buffon, Malinda L.C. and Lamontagne, Leo K. and Pollock, Tresa M. and Seshadri, Ram}
}
@article {buffon2016enhancement,
	title = {Enhancement of thermoelectric properties in the Nb{\textendash}Co{\textendash}Sn half-Heusler/Heusler system through spontaneous inclusion of a coherent second phase},
	journal = {Journal of Applied Physics},
	volume = {120},
	number = {7},
	year = {2016},
	pages = {075104},
	publisher = {AIP Publishing},
	author = {Buffon, Malinda LC and Laurita, Geneva and Verma, Nisha and Lamontagne, Leo and Ghadbeigi, Leila and Lloyd, Demetrious L and Sparks, Taylor D and Pollock, Tresa M and Seshadri, Ram}
}
@article {douglas2012enhanced,
	title = {Enhanced thermoelectric properties of bulk TiNiSn via formation of a TiNi2Sn second phase},
	journal = {Applied Physics Letters},
	volume = {101},
	number = {18},
	year = {2012},
	pages = {183902},
	publisher = {AIP Publishing},
	author = {Douglas, Jason E and Birkel, Christina S and Miao, Mao-Sheng and Torbet, Chris J and Stucky, Galen D and Pollock, Tresa M and Seshadri, Ram}
}
