Neutron diffraction and ESR studies of pseudocubic Nd0.75Ba0.25MnO3 and its unusual critical behavior above

Magnetic phase transition and clustered state in Ca-doped lanthanum cobaltite and manganite with insulator ground states

“…The extremum H position, H min , moves to smaller fields, exhibiting a minimum near T C , in qualitative agreement with the temperature dependence of the crossover condition (∼τ 5/3 ), as panels at 179.3 K and 177.5 K in figure 6(a) and the H min (T ) dependence in figure 9(b) show. At the second order transition the definite symmetry in the behavior of magnetic parameters exists relative to T C (down to a temperature of the domain formation beginning) so the position of the extremum of the matrix signal in the Re M 2 component moves again to higher fields below T C (figure 9(a)) like that in other manganites [11][12][13][14]. In our sample the cluster density is insufficient for percolation and the crystal conserves its insulator state below T C , as figure 5(b) demonstrates.…”

“…Initially the FM clusters originate in the preferable sites associated with the chemical inhomogeneities which are related to doping and oxygen nonstoichiometry. On further cooling, below some temperature T # fast growth of the isolated clusters density (homogeneous nucleation) starts, which continues down to T C where FM ordering of the matrix develops [11][12][13][14]. The present scenario corresponds to the behavior of the manganites with the FM insulator (I) ground state.…”

μSR investigation of magnetically ordered states in theA-site ordered perovskite manganitesRBaMn2Kawasaki1, Minami2, Izumi3 et al. 2012Phys. Rev. B4030View full textAdd to dashboardCite

“…All this points a weak-first order type phase transition. 24 We note that the first-order features may be related to a possible structural transition. The antiferromagnetic order is accompanied by a change in the COO superstructure.…”

“…23 Spatially inhomogeneous spin dynamics in the FM phase occurs in a variety of very different systems and go under the denomination of "Griffiths phase". 24 Not always it is possible to identify the mechanism that triggers the inhomogeneous phase. In most cases the only common characteristic of these diverse systems is the presence of strong electronic correlations, although in some particular cases chemical inhomogeneities have been named as a possible cause.…”

“…24 Not always it is possible to identify the mechanism that triggers the inhomogeneous phase. In most cases the only common characteristic of these diverse systems is the presence of strong electronic correlations, although in some particular cases chemical inhomogeneities have been named as a possible cause.…”