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The spin and quasiparticle relaxation dynamics in La$_{0.67}$Ca$_{0.33}$MnO$_{3}$ and LaMnO$_{3}$ single crystals and thin films is investigated as a function of temperature and magnetic field by pump-probe spectroscopy. The unusually slow…
We present a comprehensive ellipsometric study of an untwinned, nearly stoichiometric LaMnO_3 crystal in the spectral range 1.2-6.0 eV at temperatures 20 K < T < 300 K. The complex dielectric response along the b and c axes of the Pbnm…
A tight-band model is employed for the $e_{2g}$-orbitals in manganites. It is shown that a large intraatomic Hund's coupling, $J_H$ and the resulting double-exchange mechanism lead to antiferromagnetic ordering along one of the cubic axis…
Phase-separated manganites provide a unique platform to study the dynamics of competing electronic and structural orders in correlated systems. In La0.275Pr0.35Ca0.375MnO3 (LPCMO), we use temperature-cycling Raman spectroscopy to uncover a…
We report on the optical properties of undoped single crystal LaMnO_3, the parent compound of the colossal magneto-resistive manganites. Near-Normal incidence reflectance measurements are reported in the frequency range of 20-50,000 cm-1…
We report a 139La NMR investigation of low-doped insulating manganite samples (LaMnO(3+y) and La(1-x)Ca(x)MnO(3+y)) as a function of temperature. A volume fraction with fast nuclear relaxations was revealed by the inhomogeneous loss of the…
Recent optical conductivity measurements reveal the presence of Hubbard excitons in certain Mott insulators. In light of these results, it is important to revisit the dynamics of these materials to account for excitonic correlations. We…
We report predominantly zero field muon spin relaxation measurements in a series of Ca-doped LaMnO_3 compounds which includes the colossal magnetoresistive manganites. Our principal result is a systematic study of the spin-lattice…
In the colossal magnetoresistance manganites polarons have been proposed as the charge carrier state which localizes across the metal-insulator transition. The character of the polarons is still under debate. We present an assessment of…
The metal-insulator transition temperature in CMR manganites has been altered and brought close to the room temperature by preparing La$_{0.67}$Sr$_{0.33}$MnO$_{3}$ (LSMO)/ Nd$_{0.67}$Sr$_{0.33}$MnO$_{3}$ (NSMO) multilayers with ultra thin…
Spectral ellipsometry has been used to determine the dielectric function of an untwinned crystal of LaMnO_3 in the spectral range 0.5-5.6 eV at temperatures 50 K < T < 300 K. A pronounced redistribution of spectral weight is found at the…
We report the lattice dynamics of transition metal thin films by using the ultrafast electron diffraction. We observe a suppression of the diffraction intensity in a few picosecond after the photoexcitation, which is directly interpreted as…
The optical conductivity of the undoped PrMnO$_3$ manganite has been investigated in details at various temperatures between 300 and 4 K. Its low energy spectrum exhibits an optical gap, and is characterized by a single broad peak centered…
Direct experimental estimations of the low-energy ($1.5\sim10$ meV) complex dielectric constants spectrum and its temperature variation have been investigated for La$_{0.7}$Ca$_{0.3}$MnO$_3$ thin films using terahertz time-domain…
Neutron diffraction data presented in this paper demonstrates the relevance of lattice displacement above TC, in our understanding of the evolution of the crystal structure with temperature in the layered CMR manganite La1.2Sr1.8Mn2O7. The…
The strongly correlated material La0.7Sr0.3MnO3 (LSMO) exhibits metal-to-insulator and magnetic transition near room temperature. Although the physical properties of LSMO can be manipulated by strain, chemical doping, temperature, or…
We present optical measurements of phononic excitations in La$_{2/3}$Ca$_{1/3}$MnO$_{3}$ (LCMO) and La$_{2/3}$Sr$_{1/3}$MnO$_{3}$ (LSMO) thin films covering the full temperature range from the metallic ferromagnetic to the insulating…
Polycrystalline thin films of double layer manganite La_1.4Ca_1.6Mn_2O_7 (DLCMO) have been deposited by nebulized spray pyrolysis on single crystal LaAlO_3 substrates. These single phase films having grain size in the range 70-100 nm…
We present angle-resolved photoemission spectroscopy results for thin films of the three-dimensional manganese perovskite La$_{1-x}$Sr$_{x}$MnO$_{3}$. We show that the transition temperature ($T_c$) from the paramagnetic insulating to…
We use time-resolved hard x-ray diffraction to investigate the structural dynamics of the multiferroic insulator TbMnO$_3$ in the low temperature antiferromagnetic and ferroelectrically ordered phase. The lattice response following…