Low temperature thermopower and magnetoresistance of Sc-rich CeSc1-xTixGe

ENCINA, S.; PEDRAZZINI, P.; SERENI, J.G.; GEIBEL, C.

Praga

Conferencia; (SCES-2017) International Conference on Strongly Correated Electron Systems; 2017

Charles University, Praga

CeScGe is an antiferromagnet displaying an unusually high ordering temperature, TN=47 K. In CeSc1-xTixGe, Ti-doping leads first to a reduction of TN(x) and for x>0.4 to a prompt evolution to a ferromagnetic ordered state with TC(x)0.4. Such anomalies in the electrical resistivity are usually associated either to a spin densitywave order or the superzone-gaping of the Fermi surface as antiferromagnetism is established. This second alternative is more likely to occur in this system. The thermopower of the studied polycrystalline samples is small, with S(300K,x) showing a sign change from negative in CeScGe to positive for x>0.1. In these samples, S(T) displays a maximum at T~100 K and no hump but a small change in slope around TN(x). The absence of a hump in S(T) at the magnetic transition could be related to the multi-band character of this system. The magnetoresistance in fields H≤16T shows that the low temperature  Dr(H)/r changes from positive to negative with increasing x, while it is always negative for T~TN(x). We observe that the hump in r(T,H) is rather robust for samples close to stoichiometric CeScGe, implying that fields H>16 T are needed to induce ferromagnetism. For x=0.35 weno longer detect the hump for fields H~4 T. This is interpreted as a field-induced change in the ordered state, also in line with our H