The Effect of Cu Doping on Crystal Structure and Magnetoresistance in La0.73ca0.27mn1-ycuyo3 with 0 < Y < 0.19

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 La0.73Ca0.27Mn1-yCuyO3 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 Å) 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

ANALISIS STRUKTUR KRISTAL PADA PADUAN La0,1Ca0,9Mn1-xCuxO3

ANALISIS STRUKTUR KRISTAL PADA PADUAN La0,1Ca0,9Mn1-xCuxO3. Telah dilakukan sintesis dan karakterisasi paduan La0,1Ca0,9Mn1-xCuxO3 (0 ≤ x ≤ 0,20). Sintesis bahan menggunakan metode reaksi padatan (solid state method) dari oksida-oksida penyusun La2O3, CaCO3, MnO2, dan CuO. Campuran ini dimilling selama 10 jam dan dilakukan proses pemanasan pada suhu 1350 oC selama 6 jam. Bahan ini kemudian dimilling kembali selama 10 jam dan dilakukan proses pemanasan ulang pada suhu 1100 oC selama 24 jam. Hasil pengukuran dengan difraksi sinar-X (XRD) menunjukkan bahwa sintesis bahan La0,1Ca0,9Mn1-xCuxO3 memiliki fasa tunggal (single phase) dengan struktur kristal orthorombik, space group Pnma (I-62) dan parameter kisi berturut-turut untuk komposisi x = 0; 0,1; 0,15; dan 0,2 sebagai berikut : a = 5,298(1) Å, b = 7,496(2) Å dan c = 5,316(1) Å, a = 5,309(1) Å, b = 7,505(1) Å dan c = 5,306(2) Å, a = 5,327(8) Å, b = 7,534(8) Å, dan c = 5,326(4) Å, a = 5,334(1) Å, b = 7,535(1) Å dan c = 5,343(2) Å. Penambahan dopan Cu ke dalam atom Mn memberikan dampak peningkatan panjang ikatan antar atom Mn-Mn dan Mn-O

Determination of Crystal and Magnetic Structure of La0,47ca0,53mn1-ycuyo3 (0 < Y < 0.09) Using High Resolution Neutron Powder Diffractometer

Crystal and magnetic structure of La0,47Ca0,53Mn1-yCuyO3 with 0 < y < 0.09 at low and room temperature have been analyzes using High Resolution Neutron Powder Diffraction (HRPD). It is obtained that at room temperature as well as at low temperature, the samples have orthorhombic structure with Pnma space group. Increasing x value, will increase the lattice volume. At room temperature, samples have paramagnetic stucture, while at low temperature have antiferromagnetic structure. The value of magnetic moment will decrease with increasing x value

THE EFFECT OFCu-DOPING ON CRYSTAL STRUCTURE AND MAGNETORESISTANCE IN La0.73 Ca0.27 Mn1-y CuyO3 WITH 0 < y < 0.19

THE EFFECT OFCu-DOPINGON CRYSTAL STRUCTURE AND MAGNETORESISTANCE IN La0.73 Ca0.27 Mn1-y CuyO3 WITH 0 < y < 0.19. We studied the crystal structure at room temperature and low temperature, as well as themagneto resistance as a functionmagnetic field at room temperature in the compound La0.73 Ca0.27 Mn1-y CuyO3 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 Å) 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 magneto resistance

The Effect of Cu Doping and Magnetic Field on Specific Heat of La0.50ca0.50mno3

We report specific heat measurements of La0.50Ca0.50Mn1-yCuyO3 for y = 0.05, 0.15, 0.20 without and with applied magnetic field up to 9 T. In all cases, the external magnetic field does not influence the specific heat. At the temperature range of 100-270 K, as the Cu dopant is increased, the specific heat decreases. We found that at a range of 3-20 K, the specific heat contains terms proportional to T and T3, but a T3/2 term is not appear. The Debye temperature is 365 K for all samples indicating that the Cu-doping is not influencing the lattice factor β

Phase Transitions in La0.73Ca0.27Mn1-xCuxO3 (0 < X < 0.19)

We have performed resistivity measurements as a function of temperature, with and without an external magnetic field. Magnetization measurements are also done as a function of temperature M(T) as well as a function of an external magnetic field M(H) for La0.73Ca0.27Mn1-xCuxO3 compounds with 0&lt;x&lt;0.19. The samples with x = 0 and 0.06 are insulators. As for the samples with x = 0.10, 0.13, and 0.19, they undergo an insulator to metal transition as the temperature is lowered. The insulator-metal transition temperatures are 24 K, 74 K, and 69 K for x = 0.10, 0.13, and 0.19, respectively. The magnetoresistance decreases with increasing values of Cu, i.e. 75%, 72%, 64%, and 35% for x = 0, 0.06, 0.10, and 0.13 respectively. Samples in accordance with the model of crystalline metal Ln R vs. 1/T are compared to Mott insulator models Ln R vs. 1/T0.25. Based on the magnetization curve, a paramagnetic to ferromagnetic transition is observed at Curie temperature, TC, of ~ 196 K, 170 K, 140 K, 137 K, and 113 K for x = 0, 0.06, 0.10, 0.13, and 0.19 respectively