First Order Nucleation of Charge Ordered Domains inLa0.5Ca0.5MnO3Detecte

Abstract

The local magnetism and charge ordering of La 0.5 Ca 0.5 MnO 3 was investigated between room temperature and 1.3 K by means of 139 La and 55 Mn NMR. Antiferromagnetic and ferromagnetic domains are assigned unambiguously to the insulating charge ordered and the metallic state respectively. The phases are found to coexist at all temperatures below the first formation of a charge-ordered state. The two signal fractions display thermal and magnetic hysteresis, while their local fields and relaxations do not. These features and the absence of any critical behavior are characteristic of a first order F-AF transition, with ferromagnetic domains microscopically identical to the bulk metallic phase of the OMR manganite. [S0031-9007(98)

Charge, orbital, and magnetic order inNd0.5Ca0.5MnO3<

“…Similar mixing of phases has been observed in La 0.5 Ca 0.5 MnO 3 using NMR [21]: antiferromagnetic and ferromagnetic domains are found to coexist at all temperatures below the first formation of charge ordered state.…”

Charge-ordered state in half-doped Bi-based manganites studied byO17andBi209NMR

“…The grey curve is the calculated broadened spectrum assuming a gaussian distribution for both the local field 209 H loc and the quadrupole frequency νQ (see text for details). 18,19 , which is much less than those observed in this study. Two types of magnetic order, namely A-type and CE ′ -type magnetic structures were revealed at T = 1.5 K in neutron diffraction studies of polycrystalline Bi 0.5 Sr 0.5 MnO 3 .…”

Phase Separation inA-Site-Ordered Perovskite ManganiteLaBaMn2O6Probed byLaKawasaki1, Minami2, Kishimoto3 et al. 2006Phys. Rev. Lett.232210View full textAdd to dashboardCite

“…4 (a) is shown the temperature dependence of the internal field estimated from the peak frequency, where closed circles and open squares correspond to the lines from nuclei in the FM region and those of Mn 4+ in the AFI(CE) region, respectively. The internal field H F int at Mn site in the FM region decreases monoton- ically from 36.2 T at 4.2 K with increasing temperature and seems to approach zero at T C ∼ 330 K. This temperature dependence seems to be a characteristic of a second-order phase transition, as contrasted with the case in La 0.5 Ca 0.5 MnO 3 and Pr 0.7 Ba 0.3 MnO 3 exhibiting a first-order-like transition from FM to paramagnetic metal [18,19]. Note that any anomaly in H F int is not observed around 200 K below which the AFI(CE) region appears inside the FM phase.…”