Semiconductor-metal transition and magnetoresistance in (La, Ca)MnO3: Experiments and simple model

Neutron Diffraction, NMR and Magneto-Transport Properties in the Pr0.7Sr0.3MnO3 Perovskite Manganite

“…While the curvature is negative above T C , it gradually becomes positive below this temperature. A similar change in the sign of the curvature has been observed in similar compounds such as a La 0.67 Ca 0.33 MnO 3 powder sample [23], and is related to the onset of ferromagnetic order.…”

“…In both regions, MR changes almost linearly with M 2 in the low field range. Such evolution of the MR versus magnetic applied field has been observed in the stoichiometric La 0.67 Ca 0.33 MnO 3 [23]; it has often been found in ferromagnetic metals and alloys [25,26]. The evolution of MR as a function of M 2 is given in Fig.…”

The transport and magnetic properties of La–Pb–Mg–Mn–O manganites at low temperatures

“…Because the Mg 2+ ion has fixed valence +2, the partial substitution of Pb with Mg ions does not modify the concentration ratio of magnetic ions Mn 3+ and Mn 4+ and therefore the exchange interaction and implicitly Curie temperature remain practically unchanged. However, a slight increase of T c , of about 10 K, when the annealing time increases from 40 to 320 min was induced by lowering lattice parameters (see Table 1) [22] and increasing the double interaction strength. Fig.…”

Magnetic Order, Giant Magnetoresistance and Superconductivity in Oxides

“…It can be shown [9] that in eq (13) , with parameters given in Table 1. Experimental points (0) are from ref.…”

“…The values of the parameters in eq [14] that fit this data are given in Table (1) The resistance ratio p(T,O)/p(T,H) can be obtained from eqs. (8)(9)(10)(11)(12)(13)(14) and is given by (i) the activaiton energy UO~2 at low temperature. T«T ca , and high temperature, T»Tca is vanishinglly small and peaks in between these limits.…”