Magnetic Modes in Rare Earth Perovskites: A Magnetic-Field-Dependent Inelastic Light Scattering study
نویسندگان
چکیده
Here, we report the presence of defect-related states with magnetic degrees of freedom in crystals of LaAlO3 and several other rare-earth based perovskite oxides using inelastic light scattering (Raman spectroscopy) at low temperatures in applied magnetic fields of up to 9 T. Some of these states are at about 140 meV above the valence band maximum while others are mid-gap states at about 2.3 eV. No magnetic impurity could be detected in LaAlO3 by Proton-Induced X-ray Emission Spectroscopy. We, therefore, attribute the angular momentum-like states in LaAlO3 to cationic/anionic vacancies or anti-site defects. Comparison with the other rare earth perovskites leads to the empirical rule that the magnetic-field-sensitive transitions require planes of heavy elements (e.g. lanthanum) and oxygen without any other light cations in the same plane. These magnetic degrees of freedom in rare earth perovskites with useful dielectric properties may be tunable by appropriate defect engineering for magneto-optic applications.
منابع مشابه
نوسانات آزاد سیارات شبه زمین در حضور میدان مغناطیسی
we study the free oscillations of a non-rotating earth-like planet in the presence of a force free magnetic field. The model consists of a solid inner core, a liquid outer core and a solid mantle which is spherically symmetric. The lagrangian displacements are decomposed into scaloidal, poloidal and toroidal components using a gauged version of Helmholtz theorem. These components are identifi...
متن کاملThe effect of earth magnetic field on the function of nuclear medicine imaging systems (SPECT)
Background: The nuclear medicine systems are very sensitive to the variation of the magnetic field. Photomultiplier tubes amplify low energy light signal and change it into electrical current. Low magnetic field can produce some variations in uniformity and special resolution of SPECT systems. In this study, we tried to evaluate the effects of magnetic field on the function of nuclear medic...
متن کاملMagnetic properties of the Ag-In-rare-earth 1/1 approximants.
We have performed magnetic susceptibility and neutron scattering measurements on polycrystalline Ag-In-RE (RE, rare-earth) 1/1 approximants. In the magnetic susceptibility measurements, for most of the RE elements, inverse susceptibility shows linear behaviour in a wide temperature range, confirming well localized isotropic moments for the RE(3 + ) ions. Exceptionally for the light RE elements,...
متن کاملDynamic light scattering from acoustic modes in single-walled carbon nanotubes
We report here the computation and measurement of inelastic light scattering from acoustic vibrational modes in single-walled carbon nanotubes ~SWNT’s!. The measurement was made possible by the preparation of a sample of oriented SWNT’s, partially aligned by means of a magnetic field. Long-wavelength confined longitudinal acoustic modes are described by a shell model. Their interaction with lig...
متن کاملMagnetic Phase Transformation in the RE(Mn0.5B0.5)O3 Perovskites (RE is a Rare Earth Ion, B-Ni, Co)
A magnetic study of perovskites R E ( M ~ I . ~ B ~ ) O ~ (RE=Eu, Gd, Tb, Dy, Y; B=Ni, Co) is reported. It is found that investigated perovskites are nonhomogenous ferromagnets with relatively high Curie temperatures. The magnetic anisotropy of Ni-containing perovskites is much lower than that of Co-containing ones. It is supposed that domains with different charge state of ions and magnetic st...
متن کامل