Interplay between magnetism and transport in the CuCr1‐xTi1+xS4 thiospinel: evidence for a strong asymmetry between p‐ and n‐type transport. Issue 15 (12th May 2022)

• Record Type: Journal Article
• Authors: Hébert, Sylvie; Lebedev, Oleg; Maignan, Antoine
• Is Part Of: Zeitschrift für anorganische und allgemeine Chemie. Volume 648:Issue 15(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-05-12
• Subjects: thiospinel -- thermopower -- magnetothermopower -- magnetoresistance; Chemistry, Inorganic -- Periodicals; Chemistry -- Periodicals; 540
• DOI: 10.1002/zaac.202200045
• Languages: English
• ISSNs: 0044-2313

Abstract

Abstract: A series of SPS densified ceramics with five compositions of the CuCr1‐x Ti1+x S4 thiospinel has been synthesized, with x close to 0. Their structural characterization by transmission electron microscopy confirms the spinel cubic structure and coupled EDX analysis reveals a homogeneous cation distribution which content follows x. Interestingly, the transport properties as attested by Seebeck and Hall coefficient measurements demonstrate the existence of a sign change of the majority charge carriers near x=0. Moreover, values of electrical resistivity are found to be much lower and metallic for x<0 than for x>0, the latter showing a variable range hopping mechanism. When combined to the thermal conductivity values, this leads to asymmetric thermoelectric figure of merit ZT values at 700 K, near 0.2 and 0.01 for p and n type sides, respectively. These p and n type regimes are also characterized by different magnitudes of negative magnetoresistance, and moreover, by a change of sign of the magnetothermopower at low T, from positive for p type to negative for electron doped compositions. This study shows the existence of a correlation between charges and spins for both n and p types of the CuCr1‐x Ti1+x S4 thiospinel, leading to an unusual positive sign of magnetothermopower in the p type case. Abstract :