Unusual peculiarities of paramagnet to ferromagnet phase transition in La0.88MnO2.91

Comparative study of heterogeneous magnetic state above TC in La0.82Sr0.18CoO3 cobaltite and La0.83Sr0.17MnO3 manganite

“…2a for Re M 2 (H) at 244.5 and 225.6 K shows, this signal almost disappears at 225.6 K. Fig. 2a for Re M 2 (H) also indicates that the response of the initial F clusters shifts to a stronger H and is not seen at 225.6 K. Most likely it is the effect of the matrix response (as observed earlier [5][6][7]) since Im M 2 (H) at 258.1 K (Fig. 2b) demonstrates clearly the presence of the signal from the clusters and matrix.…”

“…Measurements of the second harmonic of the longitudinal magnetization, M 2 , in parallel dc-and ac-harmonic magnetic fields H(t)¼Hþh sin ot (hr35 Oe, o/2p¼15.7 MHz) allow one to determine reliably T n and control T-evolution of the clustered state since this method is extremely sensitive to the appearance of a F fraction in a sample. It was demonstrated by our studies of this regime in the Nd 1 À x Ba x MnO 3 and La 0.88 MnO x manganites [5][6][7]. The Re M 2 (H) and Im M 2 (H) parts of the M 2 were simultaneously recorded as functions of a steady magnetic field H for various sample temperatures (95-315 K).…”

“…However, the mechanisms of PS and properties of the phaseseparated state remain the subject of much discussion. Recently formation of an inhomogeneous magnetic state at some T n above the Curie temperature, T C , caused by origination of the ferromagnetic (F) metallic (M) clusters in the paramagnetic matrix was revealed in the doped by different ways La 1 À x Ca x MnO 3 , Nd 1 À x Ba x MnO 3 (NBMO) and La 0.88 MnO x manganites with metallic [2][3][4][5] as well as insulating (I) [6,7] ground states. The properties of this state in different compounds appear to be quite similar that suggests a possible universality of this feature in manganites, exhibiting the F ordering.…”

Unusual scenario of the temperature evolution of magnetic state in novel carbon-based nanomaterials

“…The applied method permits us to detect formation of the FM clusters in a PM media and to trace temperature evolution of the cluster subsystem, due to its extreme sensitivity to the FM fraction of a sample. This has been demonstrated by our investigations of the Nd 1−x Ba x MnO 3 and La 0.88 MnO x manganite perovskites [16,17].…”

Estimation of characteristic size of ferromagnetic clusters forming above T$_C$ in Nd$_{0.75}$Ba$_{0.25}$MnO$_3$ manganite

“…The unconventional behavior was attributed to the F metallic regions which originate in the P matrix. The F clusters as well as the unconventional behavior above T C were found in the other doped manganites [8][9][10][11][12][13]. This suggests that this phenomenon is an intrinsic property of these compounds.…”