Peculiar ferromagnetic insulator state in the low-hole-doped manganites

Mn55NMR and magnetization studies ofLa0.67Sr0.33Sidorenko1, Allodi2, Renzi3 et al. 2006Phys. Rev. B283191View full textAdd to dashboardCite

“…The localized Mn 4+ state gives rise to a peak between 310 and 330 MHz. 18,19,20,21 The localized Mn 3+ resonance strongly depends on the local spin and orbital directions. Its spectral position was shown to vary between 250 MHz and 450 MHz in a Mn ferrimagnetic spinel, in which the spin orientation could be controlled experimentally.…”

“…22 The peculiar orbital and spin structure of pseudocubic manganites confines the Mn 3+ in the range 350-430 MHz, easily distinguished from the Mn 4+ contribution. 18,19,20,21 Finally, the signal corresponding to the Mn DE state from the mixed valence metallic region is associated with a fast hopping of electrons among Mn sites and it shows up as a relatively narrow peak at an intermediate frequency in the 370-400 MHz range.…”

Changeover from glassy ferromagnetism of the orbital domain state to long-range ferromagnetic ordering inLa0.9Sr0.1MnO3

“…25 Recent studies from neutron diffraction, small angle neutron scattering and nuclear magnetic resonance shows that the ground state of La 0.9 Ca 0.1 MnO 3 consists of disordered double exchange metallic clusters that co-exists with long range superexchange based ferromagnetic insulating regions. 6 Hence the above reports show a wide variety of possibilities of the low temperature phase and ground state of such low doped FI manganites.…”

Spin-polarized tunneling spectroscopic studies of the intrinsic heterogeneity and pseudogap phenomena in colossal magnetoresistive manganiteLa0.7Ca0.3MnO3Hughes1, Beyer2, Yeh3 2010Phys. Rev. B6020View full textAdd to dashboardCite

“…Nonetheless, experimental data and theoretical calculations have suggested that the ground states of the manganites tend to be intrinsically inhomogeneous as the result of their strong tendencies toward phase separation and the phase separation may involve domains of ferromagnetic metals, ferromagnetic insulators, and antiferromagnetic chargeand orbital-ordered insulators. 9,[12][13][14][15][16] In fact, it has been demonstrated numerically that the double-exchange interaction and half metallicity alone cannot account for the large magnitude of negative magnetoresistance in ferromagnetic manganites, 9 and that the tendencies toward phase separation in the ground state even for the nominally metallic ferromagnetic phases play an essential role in the occurrence of the CMR effects. 9 From the viewpoint of technological applications, the intrinsic electronic heterogeneity of the manganites becomes a relevant concern for consistently fabricating miniaturized spintronic devices with high areal densities.…”