THE EFFECT OF Cu DOPING ON CRYSTAL STRUCTURE AND MAGNETORESISTANCE IN La 0.73 Ca 0.27 Mn 1-y Cu y O 3 WITH 0

Abstract

We studied the crystal structure at room temperature and low temperature, as well as the magnetoresistance as a function magnetic field at room temperature in the compound La 0.73 Ca 0.27 Mn 1-y Cu y O 3 with 0 < y < 0.19. To analyze the crystal structure we used X-Ray Diffractometer (XRD) at room temperature and the neutron-powder-diffraction at room temperature and low temperatures. The neutron powder diffraction experiments were under taken with the High Resolution Powder Diffractometer (HRPD) (λ=1.8223 A) at the Neutron Scattering Center of BATAN using the fullprof program. To analyze the magnetoresistance, we used a four point probe aparatus in the range ofmagnetic fields 0-7600 Oersted. We have found that no change in crystal structure despite of increasing value of y. All samples have structure orthorhombic with space group P nma, but the volume of lattice in low temperature is smaller than room temperature. At room temperature, increasing the value y impact declining value of magnetoresistance. Keywords: Crystal structure, HRPD, Fullprof program, Magnetoresistance