arXiv subjects

G. Le Bras-Jasmin

Publications and source records attributed to G. Le Bras-Jasmin.

3 recordsLinked to original sources

arXiv2009

Magnetization and magneto-electric effect in La-doped BiFeO3

We report on magnetisation and magneto-capacitance measurements in the Bi1-xLaxFeO3 series for 0 < x < 0.15. We confirm that doping with La reduces the threshold magnetic field Hc for cancelling the magnetic spiral phase, and we show that Hc decreases as the La content increases up to x=0.15, which is the highest concentration for maintaining the non-centrosymmetric rhombohedral structure of BiFeO3. Measurements of the dielectric constant as a function of magnetic field in the series also show a maximum magneto-capacitance for x=0.15.

cond-mat.str-el↗

arXiv2002

Thermopower in Overdoped Region of Cuprates

The thermoelectric power S(T) of single-layer Bi2Sr2CuO6+d is studied as a function of oxygen doping in the strongly overdoped region of the phase diagram (T, d). As other physical properties in this region, diffusion thermopower Sdiff(T) also shows an important deviation from conventional Fermi liquid behaviour. This departure from T-linear S(T) dependence together with the results of susceptibility on the same samples suggest that the origin of the observed non-metallic behaviour is the existence of a singularity in the density of states near the Fermi level. The doping and temperature dependence of themopower is compared with a tight-binding band model.

cond-mat.supr-con↗

arXiv2002

Anomalous Electronic Susceptibility in Bi2sr2cuo6+d

We report magnetic susceptibility performed on overdoped Bi2Sr2CuO6+d powders as a function of oxygen doping d and temperature T. The decrease of the spin susceptibility chis with increasing T is confirmed. At sufficient high temperature, chis presents an unusual linear temperature dependence chis=chis0 -chi1T . Moreover, a linear correlation between chi1 and chis0 for increasing hole concentration has been displayed. These non conventional metal features will be discussed in terms of a singular narrow-band structures.

cond-mat.supr-con↗