Low-Temperature Properties of CePt_3P Tuned by Magnetic Field

We present low-temperature magnetization, magnetoresistance and specific heat measurements on the Kondo lattice compound CePt_3P under applied magnetic fields up to 9.0 T. At zero field, CePt_3P exhibits a moderately enhanced Sommerfeld coefficient of electronic specific heat \gamma_\rm Ce=86 mJ/mol\cdotK^2 as well as two successive magnetic transitions of Ce 4f moments: an antiferromagnetic ordering at T_\rm N1=3.0 K and a spin reorientation at T_\rm N2=1.9 K. The value of T_\rm N1 shifts to lower temperature as magnetic field increases, and it is ultimately suppressed around B_\rm c\sim 3.0 T at 1.5 K. No evidence of non-Fermi liquid behavior is observed around B_\rm c down to the lowest temperature measured. Moreover, \gamma decreases monotonously with increasing the magnetic field. On the other hand, the electrical resistivity shows an anomalous temperature dependence \rho\propto T^n with the exponent n decreasing monotonously from \sim2.6 around B_\rm c down to \sim1.7 for B=9.0 T. The T–B phase diagram constructed from the present experimental results of CePt_3P does not match the quantum criticality scenario of heavy fermion systems.