Control of thermoelectric properties in Mn-substituted Fe2TiSi epilayers

Epitaxial Mn2VAl films with L21-ordered structure for all-Heusler stacks

“…We have developed techniques for the growth of some full-Heusler alloys by low-temperature molecular beam epitaxy (MBE). Unlike most thin-film studies on full-Heusler alloys, relatively high degrees of structural ordering have been obtained at less than 350 • C [10,12,[33][34][35][36][37][38][39][40][41][42][43][44]. These low-temperature MBE techniques have also enabled all-Heusler stacks with sharp heterointerfaces [45,46].…”

Thermoelectric properties of composition-controlled Fe2TiSi-based full-Heusler thin films

“…7,8) It is effective to make use of the seed effects from substrates as investigated in the field of spintronics by using MgO 9) and thermoelectrics by using MgAlO 4 for Fe 2 TiSi. [10][11][12] In thin films, another difficulty is to control the valence electron concentration (VEC) to around 6.00, where FH alloys have a high thermoelectric performance. 3,13) Meanwhile, we succeeded to achieve precise control of film compositions by utilizing sputtering techniques in Fe 2 VAl-and Fe 2 TiAl-based thin films.…”

“…15) It should be noted that S and ρ can be improved by employing other substrates with a small lattice mismatch, such as MgAlO 4, to achieve better crystallinity as previously reported. [10][11][12] The out-of-plane κ at RT was 3.5 W K −1 m −1 ., which is small in comparison to the typical Fe 2 VAl FH bulks. As a result, ZT was 0.36 at room temperature without heavy element doping, which is high enough in FH.…”