Article

Magnetic and optical properties of Mn-doped BaSnO3

Solid State Communications (Impact Factor: 1.7). 06/2009; 149:884-887. DOI: 10.1016/j.ssc.2009.02.037

ABSTRACT Polycrystalline samples of BaSn1−xMnxO3 with x=0, 0.01, 0.02, 0.03, 0.04 and 0.05 were prepared by solid state reaction method. Using the powder X-ray diffraction patterns, these samples were found to be free of secondary phases. The substitution of Mn for Sn is also evidenced by the gradual disappearance of the characteristic optical band gap absorption (at 3.1 eV) and disappearance of Raman modes (centered around 835 cm−1, 1157 cm−1 and 1473 cm−1) of the host BaSnO3 with increasing Mn-content. The field dependent magnetization data collected at 300 K show that the undoped BaSnO3 is diamagnetic; upon doping Mn, the diamagnetic character of BaSnO3 diminishes and the ferromagnetic character evolves gradually with increasing Mn-content. The presence of F-centers in the samples is witnessed by the electron spin resonance (ESR) spectrum and the first order Raman spectrum of BaSnO3. At room temperature, the electrical resistivity of Mn-doped BaSnO3 is of the order of 108 Ω m. These results suggest that the ferromagnetism in these systems is due to F-center exchange interaction. The observed ferromagnetism in these samples is also supported by ESR spectra.

0 Followers
 · 
218 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: Room-temperature ferromagnetism was observed in transparent Mn-doped BaSnO3 (BSMO) films epitaxially grown on SrTiO3 substrates by pulsed laser deposition. X-ray photoelectron spectroscopy and X-ray absorption near-edge structure spectra analysis revealed that Mn2+ is the primary Mn ion in the BSMO films. The high saturated magnetization of BSMO films grown at a low oxygen pressure can be attributed to the effective exchange coupling interaction between oxygen vacancies and magnetic Mn ions. Further, the band gap energy of the BSMO films increases from 3.27 to 3.74 eV with decreasing growth oxygen pressure. The results demonstrate that Mn-doped BaSnO3 films may be useful in integrated magneto-optical device applications.
    Applied Physics Express 03/2014; 7(3):033006. DOI:10.7567/APEX.7.033006 · 2.57 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In this paper, we report on structural and optical properties of terbium and europium doped barium stannate phosphors (BaSnO3) synthesised by conventional solid state reaction method. We have studied those materials by using X-ray diffraction (XRD), radioluminescence (RL) and photoluminescence (PL) techniques. XRD patterns confirm that the BaSnO3 sintered at 1400 degrees C exhibit orthorhombic structure and that the Tb3+ and Eu3+ substitution of Ba2+ does not change the structure of the BaSnO3 host. The optical emission spectrum is characterized a broad band centered at 897 nm (1.38 eV), with a high-energy tail approximately 750 nm from the host lattice. Other emission signals that are characteristic of the 3 + oxidation state of rare earth elements were generated by Eu and Tb doping. Luminescence measurements show that the series of emission states D-5(4) -> F-7(6), D-5(4) -> F-7(5), D-5(4) -> F-7(4) and D-5(4) -> F-7(3) corresponding to the typical (4)f -> (4)f infra-configuration forbidden transitions of Tb3+ are appeared and the major emission peak at 540 nm is due to D-5(4) -> F-7(5) transitions of Tb3+. On the other hand, the emission spectrum of Eu doped BaSnO3 phosphor exhibits a series of emission bands, which are attributed to the D-5(0) -> F-7(j) (j = 0-4) transitions of Eu3+ ions. The dominant emission of Eu3+ corresponding to the electric dipole transition D-5(0) -> F-7(2) is located at 613 nm. The sharp emission properties exhibited demonstrate that the BaSnO3 is a suitable host for rare-earth ion doped phosphor material. This work clearly confirms the unusual near infrared (NIR) PL discovered by H. Mizoguchi et al. in BaSnO3 at room temperature.
    Journal of Alloys and Compounds 03/2014; 590:417-423. DOI:10.1016/j.jallcom.2013.12.135 · 2.73 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: On-line measurements of ultrasonic longitudinal velocity, shear velocity and longitudinal attenuation were carried out on R1-xSrxMnO3 perovskites (R=La, Pr, Nd and Sm) for different compositions of Sr, at a fundamental frequency of 5MHz over wide range of temperatures using the through-transmission method. The observed maxima/minima in velocities and attenuation have been discussed with decrease in ionic radii and composition. As a decrease in the ionic radii of rare earth elements leads to a decrease in transition temperature (Tc), the results that are observed show that measurement is one of the best tools to explore the structural/phase transition on-line velocity in perovskite manganese materials as a function of the ionic radii of rare earth elements.
    Materials Research 08/2012; 15(4):517-521. DOI:10.1590/S1516-14392012005000067 · 0.48 Impact Factor