Defect induced ferromagnetism in h-BaTiO3 synthesized from t-BaTiO3 by microwave heating

Ramaraghavulu Rajavaram, Junwoo Park, Joonho Lee

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Structure modification of tetragonal BaTiO3 (t-BaTiO3) and corresponding phase transition by microwave heating were investigated. The sample compound was heated by 1.8 kW power and 2.45 GHz frequency microwave irradiation under N2 atmosphere in a short experimental duration of 14 min. The maximum temperature of the surface of the sample was 1115 °C. The structure of the microwave irradiated BaTiO3 was then analyzed by employing X-ray diffraction (XRD), Rietveld refinement analysis, Raman spectroscopy, and field emission scanning electron microscopy techniques. From XRD and Rietveld refinement analysis, the microwave irradiated BaTiO3 sample was composed of hexagonal 89%, cubic 5% and tetragonal 6%. Due to the direct internal heating mechanism of microwaves, the core temperature of the sample might be higher than the phase transition temperature. The magnetic behavior of the sample was investigated using a vibrating sample magnetometer. The results indicated that the microwave irradiated BaTiO3 exhibited mixed magnetism: ferromagnetic nature at low applied magnetic fields and diamagnetic nature at high applied magnetic fields.

Original languageEnglish
Pages (from-to)627-632
Number of pages6
JournalJournal of Alloys and Compounds
Volume712
DOIs
Publication statusPublished - 2017 Jul 25

Fingerprint

Microwave heating
Ferromagnetism
Microwaves
Defects
Rietveld refinement
Phase transitions
Magnetic fields
X ray diffraction
Microwave irradiation
Magnetism
Magnetometers
Field emission
Superconducting transition temperature
Raman spectroscopy
Heating
Temperature
Scanning electron microscopy

Keywords

  • BaTiO
  • Magnetic properties
  • Microwave processing
  • Rietveld refinement

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

Cite this

Defect induced ferromagnetism in h-BaTiO3 synthesized from t-BaTiO3 by microwave heating. / Rajavaram, Ramaraghavulu; Park, Junwoo; Lee, Joonho.

In: Journal of Alloys and Compounds, Vol. 712, 25.07.2017, p. 627-632.

Research output: Contribution to journalArticle

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abstract = "Structure modification of tetragonal BaTiO3 (t-BaTiO3) and corresponding phase transition by microwave heating were investigated. The sample compound was heated by 1.8 kW power and 2.45 GHz frequency microwave irradiation under N2 atmosphere in a short experimental duration of 14 min. The maximum temperature of the surface of the sample was 1115 °C. The structure of the microwave irradiated BaTiO3 was then analyzed by employing X-ray diffraction (XRD), Rietveld refinement analysis, Raman spectroscopy, and field emission scanning electron microscopy techniques. From XRD and Rietveld refinement analysis, the microwave irradiated BaTiO3 sample was composed of hexagonal 89{\%}, cubic 5{\%} and tetragonal 6{\%}. Due to the direct internal heating mechanism of microwaves, the core temperature of the sample might be higher than the phase transition temperature. The magnetic behavior of the sample was investigated using a vibrating sample magnetometer. The results indicated that the microwave irradiated BaTiO3 exhibited mixed magnetism: ferromagnetic nature at low applied magnetic fields and diamagnetic nature at high applied magnetic fields.",
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N2 - Structure modification of tetragonal BaTiO3 (t-BaTiO3) and corresponding phase transition by microwave heating were investigated. The sample compound was heated by 1.8 kW power and 2.45 GHz frequency microwave irradiation under N2 atmosphere in a short experimental duration of 14 min. The maximum temperature of the surface of the sample was 1115 °C. The structure of the microwave irradiated BaTiO3 was then analyzed by employing X-ray diffraction (XRD), Rietveld refinement analysis, Raman spectroscopy, and field emission scanning electron microscopy techniques. From XRD and Rietveld refinement analysis, the microwave irradiated BaTiO3 sample was composed of hexagonal 89%, cubic 5% and tetragonal 6%. Due to the direct internal heating mechanism of microwaves, the core temperature of the sample might be higher than the phase transition temperature. The magnetic behavior of the sample was investigated using a vibrating sample magnetometer. The results indicated that the microwave irradiated BaTiO3 exhibited mixed magnetism: ferromagnetic nature at low applied magnetic fields and diamagnetic nature at high applied magnetic fields.

AB - Structure modification of tetragonal BaTiO3 (t-BaTiO3) and corresponding phase transition by microwave heating were investigated. The sample compound was heated by 1.8 kW power and 2.45 GHz frequency microwave irradiation under N2 atmosphere in a short experimental duration of 14 min. The maximum temperature of the surface of the sample was 1115 °C. The structure of the microwave irradiated BaTiO3 was then analyzed by employing X-ray diffraction (XRD), Rietveld refinement analysis, Raman spectroscopy, and field emission scanning electron microscopy techniques. From XRD and Rietveld refinement analysis, the microwave irradiated BaTiO3 sample was composed of hexagonal 89%, cubic 5% and tetragonal 6%. Due to the direct internal heating mechanism of microwaves, the core temperature of the sample might be higher than the phase transition temperature. The magnetic behavior of the sample was investigated using a vibrating sample magnetometer. The results indicated that the microwave irradiated BaTiO3 exhibited mixed magnetism: ferromagnetic nature at low applied magnetic fields and diamagnetic nature at high applied magnetic fields.

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