Electrical transport under extreme conditions in the spin-ladder antiferromagnet TaFe1.25Te3

We report the electrical transport of the layered, spin-ladder antiferromagnet TaFe1.25Te3 (TN -167 K) under intense magnetic field (up to 60 T) and high pressure (up to 50 GPa). In high magnetic field, TaFe1.25Te3 undergoes two metamagnetic transitions, manifested in both the magnetoresistance and the Hall resistivity. Synchrotron x-ray diffraction reveals no obvious structural transition up to -50 GPa. However, the application of a small pressure (-0.7 GPa) fosters a sizable anomalous Hall conductivity and a negative magnetoresistance, possibly arising from the competing ferromagnetic exchange interaction in this antiferromagnet. Both the anomalous Hall conductivity and the negative magnetoresistance culminate at a pressure of -4 GPa. With further increase of pressure, both physical quantities diminish. The Hall coefficient and the magnetoresistance change sign above -20 GPa, presumably due to the cessation of ferromagnetic spin fluctuations in this high pressure regime.