Giant volume magnetostriction and its connection with colossal magnetoresistance and lattice-softening La1−xMxMnO3 (M=Ca, Ag, Ba, Sr)

Magnetotransport and magnetoelastic effects in Co-doped La0.7Sr0.3MnO3 nanocrystalline perovskites

“…The behavior of o in all samples has an abrupt change: it becomes negative and passes through an extremum value in the T C region, and then with further temperature increase, it approaches zero. This unusual behavior (sample shrinkage under an applied field), which has been also observed in yttrium doped LCMO [4], is related to polaron effects and indicates the presence of a conductive MTPS (insulating AFM microregions in FM matrix) at TZT C , which is expected for our samples with a high level of Sr 2 + doping (more than 17% [3]). As mentioned, this MTPS is thermally destroyed in the T C region, resulting in an extra contribution to TE.…”

“…), have been a renewed subject of numerous investigations in recent years. The interest in them is not only because they are interesting systems exhibiting structural, magnetic and electronic transitions [1,2] but also because of their potential technological applications in various sensors and magnetomechanical devices arising from colossal magnetoresistance (CMR) and giant volume magnetostriction (GVMS) observed in certain compounds near room temperature [3][4][5][6][7][8][9]. Among a number of perovskite manganites with various combination of RE and A, La 1 À x Ca x MnO 3 and La 1 À x Sr x MnO 3 (LSMO) are prototypical and reference materials; however LSMO family has been studied much less.…”

“…[12]. In compounds with high doping levels (x Z0.17 for A ¼Sr [3,7]), such FM regions grow and insulating AFM microregions are present in the conducting FM matrix. The cause of this magnetic two-phase state (MTPS) in manganites, which is confirmed experimentally by various methods including SEM and neutron scattering (e.g.…”

“…It has been found that a significant VMS effect around T c is a common feature of all manganites [3][4][5][6][7][8][9]14] (it should be noted that the concept of T C in MTPS is rather conditional, it is T C of the FM part). So far, several mechanisms have been proposed for the MS effect in manganites, for example, Asamitsu et al [1,2] attributed the observed GVMS in La 0.83 Sr 0.17 MnO 3 single crystals to the structural transition caused by the applied magnetic field , or Koroleva et al [3,7,12] explained the GVMS effect in La 0.7 Sr 0.3 MnO 3 single crystals on the basis of formation of small polarons and presence of FM/AFM two-phase state (MTPS) due to strong s-d exchange, etc. However, GVMS is not observed in conventional magnetic semiconductors with MTPS and CMR, since their lattices are rigid and the exchange s-d interaction is insufficient to overcome the electrostatic forces between ions [7].…”

Peculiar Electrical and Magnetic Properties of La(Ba)MnO₃ Thin Films

“…The anisotropic anomalous T-dependence of Γ pp around 150 K might be related to the magnetostriction effect. We should investigate hereafter whether the magnetostriction model is really effective or not [33][34][35][36]. It is suggested that the FMR is very unique and important technique in this research work.…”