Effect of double exchange on thermoelectric power of CuxCoyCrzSe4

Thermoelectric Power Studies Cu-Cd Ferrites

“…The negative value of thermoelectric power found over the entire temperature range studied that the majority charge carriers are electrons. A similar thermo electric power with the temperature was observed in [5][6][7][8]. Copyright © 2012 SciRes.…”

Influence of Cr-Substitution on the Electrical Properties of Fe_{1-x}Cr_xVSbO_6

“…The nature of these states can be linked with the existence of the structure defects and the grain-boundaries with the depletion layers of the adjacent grains. From the other side simultaneous growth of the magnetic moment as well as the electrical conduction, particularly at low temperatures can point out to the presence of chromium ions with the dierent valence [13], as it was for example observed in Zn 1−x Cu x Cr 2 Se 4 [13], Zn x Cu y Cr z Se 4 [14] and Cu x Co y Cr z Se 4 [15] spinel series.…”

Correlation between the negative magnetoresistance effect and magnon excitations in single-crystalline CuCr1.6V0.4Se4

“…We have shown that in ferromagnetic semiconductor CuCr 1.6 V 0.4 Se 4 , exhibiting high electrical conductivity the magnon excitations are connected with a double exchange mechanism existing apart from the superexchange interaction, like it was observed in the ferromagnetic spinel systems: Zn x Cu y Cr z Se 4 for y ≥ 0.8 [11], Cu x Ga y Cr z Se 4 for 0.036 ≤ y ≤ 0.394 [12], Cu x Co y Cr z Se 4 for 0.06 ≤ y ≤ 0.11 [13], and indicated by de Gennes in manganites [35]. For comparison, in the CdCr 2-x Ga x Se 4 spinel system [10] 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 …”

“…1) can be easily fitted by the modified Matoba, Anzai and Fujimori semiempirical formula [31] including the magnetic contribution [13] as follows: Table 2). …”

“…Recently, numerous efforts have been made to find a correlation between the thermoelectric power and the double exchange and superexchange interactions in the CdCr 2-x Ga x Se 4 , Zn x Cu y Cr z Se 4 , Cu x Ga y Cr z Se 4 and Cu x Co y Cr z Se 4 spinel series [10][11][12][13][14]. These studies have shown that the strong ferromagnetic coupling connected mainly with the double-exchange mechanism, makes easier both the magnon excitations and a transfer of the phonon momentum to the electron gas.…”