Physical and Magnetic Properties of La0.5Ca0.5Mn0.9Cu0.1O3 at Temperature in the Range of 10-100 K

Abstract

We have successfully measured physical and magnetic properties of the La0.5Ca0.5Mn0.9Cu0.1O3 at temperature in the range of 10-100 K. Physical properties have covered electrical resistivity and specific heat. The properties, which serve as a function of temperature, were investigated by using Physics Properties Measurement System (PPMS) with and without an external magnetic field up to 8.5 Tesla. The magnetic structure was characterized using High-Resolution Powder Diffraction (HRPD) at room and low temperatures. Furthermore, the magnetization was measured by using Magnetic Properties Measurement System (MPMS) with the external magnetic field of 0-7 Tesla. In the temperature interval of 10-53 K, the resistivity of the sample increased with the increasing of external magnetic field. At temperatures T < 53 K, the samples were crystalline metal. This was revealed by fitting the graph Ln R as a function of 1/T. At temperatures T > 53 K, the sample was an insulator according to fittings Ln R as a function of 1/T0.25. The result was also shown by the decreasing value of the resistivity of the sample. The transition temperature of the metal-insulator (TMI) decreased with the increasing of external magnetic field, i.e. from 60 K without an external magnetic field to 53 K with external magnetic field 8.5 Tesla. A coefficient electron specific heat and specific heat of spin wave increased, and phonon specific heat was relatively unchanged in the presence of an external magnetic field. Results of HRPD experiment were analyzed by using Fullprof program. At room temperature, the sample had the paramagnetic phase, while at low temperatures of 20 K it had antiferromagnetic phase. Temperature phase transition from the paramagnetic to antiferromagnetic phase or Neel temperature was around 225 K. However, the saturation magnetization of the sample was not observed.