title: Magnetic Modes in Rare Earth Perovskites: A Magnetic-Field-Dependent Inelastic Light Scattering study.
abstract: Here, we report the presence of defect-related states with magnetic degrees of freedom in crystals of LaAlO3and 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 LaAlO3by Proton-Induced X-ray Emission Spectroscopy. We, therefore, attribute the angular momentum-like states in LaAlO3to 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.
authors.affiliation: NUSNNI-NanoCore, 5A Engineering Drive 1, National University of Singapore, 117411, Singapore.|Department of Physics, 2 Science Drive 3, National University of Singapore, 117542, Singapore.
authors.forename: Surajit
authors.initials: S
authors.lastname: Saha
authors.affiliation: Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 637371, Singapore.
authors.forename: Bing-Chen
authors.initials: BC
authors.lastname: Cao
authors.affiliation: NUSNNI-NanoCore, 5A Engineering Drive 1, National University of Singapore, 117411, Singapore.|Department of Physics, 2 Science Drive 3, National University of Singapore, 117542, Singapore.
authors.forename: M
authors.initials: M
authors.lastname: Motapothula
authors.affiliation: Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 637371, Singapore.
authors.forename: Chun-Xiao
authors.initials: CX
authors.lastname: Cong
authors.affiliation: NUSNNI-NanoCore, 5A Engineering Drive 1, National University of Singapore, 117411, Singapore.|Department of Physics, 2 Science Drive 3, National University of Singapore, 117542, Singapore.
authors.forename: Tarapada
authors.initials: T
authors.lastname: Sarkar
authors.affiliation: NUSNNI-NanoCore, 5A Engineering Drive 1, National University of Singapore, 117411, Singapore.|Department of Physics, 2 Science Drive 3, National University of Singapore, 117542, Singapore.
authors.forename: Amar
authors.initials: A
authors.lastname: Srivastava
authors.affiliation: NUSNNI-NanoCore, 5A Engineering Drive 1, National University of Singapore, 117411, Singapore.|NUS Graduate School for Integrative Sciences and Engineering, 28 Medical Drive, National University of Singapore, 117456, Singapore.
authors.forename: Soumya
authors.initials: S
authors.lastname: Sarkar
authors.affiliation: NUSNNI-NanoCore, 5A Engineering Drive 1, National University of Singapore, 117411, Singapore.|NUS Graduate School for Integrative Sciences and Engineering, 28 Medical Drive, National University of Singapore, 117456, Singapore.
authors.forename: Abhijeet
authors.initials: A
authors.lastname: Patra
authors.affiliation: NUSNNI-NanoCore, 5A Engineering Drive 1, National University of Singapore, 117411, Singapore.
authors.forename: Siddhartha
authors.initials: S
authors.lastname: Ghosh
authors.affiliation: NUSNNI-NanoCore, 5A Engineering Drive 1, National University of Singapore, 117411, Singapore.|Department of Physics, 2 Science Drive 3, National University of Singapore, 117542, Singapore.
authors.lastname: Ariando
authors.affiliation: NUSNNI-NanoCore, 5A Engineering Drive 1, National University of Singapore, 117411, Singapore.|School of Physics and Centre for Research on Adaptive Nanostructures and Nanodevices, Trinity College, Dublin, Ireland.
authors.forename: J M D
authors.initials: JM
authors.lastname: Coey
authors.affiliation: Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 637371, Singapore.
authors.forename: Ting
authors.initials: T
authors.lastname: Yu
authors.affiliation: NUSNNI-NanoCore, 5A Engineering Drive 1, National University of Singapore, 117411, Singapore.|Department of Physics, 2 Science Drive 3, National University of Singapore, 117542, Singapore.|NUS Graduate School for Integrative Sciences and Engineering, 28 Medical Drive, National University of Singapore, 117456, Singapore.|Department of Electrical and Computer Engineering, National University of Singapore, 117576, Singapore.
authors.forename: T
authors.initials: T
authors.lastname: Venkatesan