Linear magnetoresistance and structural distortion in layered SrCu_4-x P₂ single crystals

We report a systematic study on layered metal SrCu4-xP2 single crystals via transport, magnetization, thermodynamic measurements and structural characterization. We find that the crystals show large linear magnetoresistance without any sign of saturation with a magnetic field up to 30 T. We also observe a phase transition with significant anomalies in resistivity and heat capacity at T-p similar to 140 K. Thermal expansion measurement reveals a subtle lattice parameter variation near T-p, i.e., Delta L-c/L-c similar to 0.062%. The structural characterization confines that there is no structure transition below and above T-p. All these results suggest that the nonmagnetic transition of SrCu4-xP2 could be associated with structural distortion.