Polaron freezing and the quantum liquid-crystal phase in the ferromagnetic metallic La0.67Ca0.33MnO3

Abstract

The remarkable electronic properties of colossal magnetoresistive manganites are widely believed to be caused by the competition between a ferromagnetic metallic state and an antiferromagnetic insulating state with complex spin, charge, and orbital ordering. However, the physics underlying their magnetotransport properties is still not clear, especially the role of correlated Jahn-Teller polarons, which depending on temperature and doping, might form a liquid, glass or stripe polaron state. This question touches one of the most fundamental problems in the physics of doped Mott insulators, i.e. understanding the mechanism that chemical doping makes an insulator becoming superconductive as in the case of cuprates, or exhibiting the colossal magnetoresistance effect, as in the case of manganites. Here, by using 139 La NMR and high resolution transmission electron microscopy in the temperature range 3.2-1000 K, we have monitored the formation and evolution of CE-type polarons in optimally doped La 0.67 Ca 0.33 MnO 3 . While NMR experiments show that correlated polarons dominate electron spin dynamics in the ferromagnetic phase, at very low temperatures they appear to form a quantum liquid-crystal like ferromagnetic phase, embedded into a ferromagnetic matrix with 3D polaron correlations. This is evidence that similarly to high T c cuprates, quantum soft phases underlie the exotic physical properties of colossal magnetoresistive manganites.

Local orbital degeneracy lifting as a precursor to an orbital-selective Peierls transition

“…Interestingly, in CuIr 2 S 4 it is not the formation of the ODL objects, but their ordering that precipitates the MIT and magnetic dimer formation of the ground-state. The fluctuating ODL state is stabilized electronically by breaking d-electron orbital degeneracies and as such is likely to be a phenomenon that is widespread, though not widely appreciated, among the many materials with incompletely filled d-electron manifolds [21,22], many of which have important emergent low temperature electronic and magnetic behaviors, from classics such as manganites [11,23,24], cuprates [4,9,25], and iron chalcogenides/pnictides [7,10,[26][27][28][29], to materials featuring exotic low-temperature orbital molecules [30,31]. It may also explain the unexpected observation of phonon-glass-like thermal conductivity in various transition metal oxides [32] The low temperature insulating state in CuIr 2 S 4 [33][34][35] consists of ordered Ir 3+ (5d 6 ) and Ir 4+ (5d 5 ) ions [36], with a four-fold periodicity, an example of tetrameric charge ordering [37].…”

Magnetic Field-driven Insulator–Metal Transition and Colossal Magnetoresistance of Metamagnetic Semiconductor Mercury Thiodichromite Crystals

“…Thus, it is necessary to search some microscopic evidence for magnetic polaron, which can be probed by different kinds of method such as muon spin rotation, 42,43 Raman scattering, 44 and nuclear magnetic resonance. 45,46 ESR is also a powerful technique to detect magnetic polaron; 47−49 therefore, we present temperature- In the high-temperature range (Figure 6c), each spectrum contains a single resonance signal with a Lorentzian line shape except at lower temperatures such as 70 K, where the spectrum line is slightly distorted reflecting from different heights of the peak and the valley. The ESR spectrum line at 70 K seems to contain multiple resonance signal, so is somewhat different with that at 60 K for a previously grown single crystal by other groups.…”

“…Those semiquantitative analyses is suitable only for a typical ferromagnet, but not for metamagnetic HCS. Thus, it is necessary to search some microscopic evidence for magnetic polaron, which can be probed by different kinds of method such as muon spin rotation, , Raman scattering, and nuclear magnetic resonance. , ESR is also a powerful technique to detect magnetic polaron; − therefore, we present temperature-dependent ESR spectra of single crystal in the following. Figure a–c displays ESR spectra at some representative points in the low, intermediate, and high temperature ranges, respectively.…”

Review of the Influence of Acrylate Lotion on the Properties of Cement-Based Materials

“…The corrosion resistance of cement-based materials modified by acrylate lotion to acid, alkali, salt, and other chemicals has also been improved [39]. Meanwhile, as a new type of additive, TiO 2 has a unique impact on modifying cement-based materials, attracting researchers' interest [40][41][42][43]. The outstanding contributions from Kurda et al [44] in predicting the strength of cement-based materials with artificial intelligence and the application of polymer-modified cement-based materials in 3D printing technology [45] are also highly anticipated.…”