Electrical properties and enhanced room temperature magnetoresistance in (La0.7Ca0.2Sr0.1MnO3)1−x/Pdx composites

Observance of Improved Magneto-resistance and Magnetic Entropy Change in La0.7(Ca0.2Sr0.1)MnO3:Pd Composite

“…These samples were not in a melted state and the observed behavior could be attributed to the coalescence of smaller grains and forming bigger size grains. Further, due to the higher sintering temperature of 1400 • C used in synthesis of the materials, PdO gets converted into metallic Pd (PdO dissociation temperature being ∼750 • C) [8,9,12,13]. Elemental analysis performed using EDS attachment to SEM confirms the presence of Pd in the LCSMO:Pd10 composite (Table 2).…”

“…The hump around 230 K in the pristine LCSMO sample represents the conduction through grain boundaries which offer some resistive path to the carriers at lower temperatures. Incorporation of Pd makes grain boundaries conducting and therefore the overall resistivity of the LCSMO:Pd10 sample decreases [8,9,12,13]. The hump disappears (due to this lower resistance) due to metallic Pd within grain boundaries and tunneling of the carriers across them.…”

“…Efforts are being carried out to obtain sizable MR values at low fields (LFMR) and near room temperature [8,9]. Several manganite materials like LCBMO, LCSMO, PBMO and their composites with Ag 2 O and PdO have been investigated to explore their potential for magnetic sensing applications [8][9][10][11][12][13]. Besides, manganites have also shown good potential as active magnetic refrigerant (AMR) near room temperature [10,[14][15][16][17].…”

“…Thus we can expect to obtain enhanced properties in the composite material. Various manganite composites have been investigated for their efficacy towards magnetic sensing and refrigeration applications [8][9][10][11][12][13][14][15][16][17] 3 and MnO 2 (all with 5 N purity). These ingredients were ground thoroughly, calcined at several steps of 900 • C for 18 h, 1100 • C for 18 h, 1300 • C for 18 h, respectively, and finally sintered at 1400 • C. Thus prepared sample was powdered and PdO was added and pelletized.…”

Magneto-transport Properties of La0.7Sr0.3Mn1+dO3-Manganese Oxide Composites Prepared by Liquid Phase Sintering

“…Since the LFMR values of pure RE 1-x A x MnO 3 perovskite maganites are insufficient for real applications, many groups have attempted to improve the LFMR effect by producing composites of manganites with second phases, such as insulating oxides [5][6][7][8][9][10][11][12][13], metals [14,15], polymers [16,17], and other manganites [18][19][20]. In comparison with a pure polycrystalline manganite, the perovskite manganite-oxide composites exhibited much improved LFMR effect, which was normally accompanied by a significant increase in their electrical resistivities and an abrupt decrease in their T C values.…”