Magnetic and Electronic Transport Properties of Single Crystal La0.64Pb0.36MnO3

ABSTRACTWe studied the magnetic and electronic transport properties of a single crystal sample of La0.64Pb0.36MnO3 in the temperature range 5 K to 350 K and magnetic field up to 5.5 T. A magnetic transition is found at 210 K. The single crystal sample is ferromagnetic below the transition temperature (Tc) and becomes paramagnetic at temperatures T > Tc. Magnetization measurements along three different orthorhombic crystal axes show no significant difference. The magnetoresistance approaches a maximum value of about -60% at Tc in 5 T magnetic field strength and has qualitatively different field dependence below and above Tc. The scaling behavior between resistivity and magnetic moment is examined for temperatures both below and above the transition. A low temperature (T<15 K) dp / dT < 0 effect is attributed to possible quantum tunneling of carriers between neighbouring distortions.