Valence Change of Mn Ions in BaTiO3‐Based PTCR Materials

Joon‐Hyung ‐H Lee; Sung‐Hee ‐H Kim; Sang‐Hee ‐H Cho

doi:10.1111/j.1151-2916.1995.tb08065.x

Valence Change of Mn Ions in BaTiO₃‐Based PTCR Materials

Joon‐Hyung ‐H Lee, Sung‐Hee ‐H Kim, Sang‐Hee ‐H Cho

Kyungpook National University

Research output: Contribution to journal › Article › peer-review

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Abstract

The effect of Mn on the PTCR characteristics of La‐doped BaTiO₃ ceramics was studied. Acceptor state density was measured from a p‐1/T graph as a function of Mn concentration. The behavior of room‐temperature resistivity with Mn concentration was explained by compensation of acceptors at grain boundaries. The valence state of Mn was analyzed by ESR, and it changed near the Curie temperature of BaTiO₃ from 3+ in tetragonal phase to 2+ in cubic phase. Therefore, the number of electron traps increased at the Curie temperature, leading to the great improvement in the PTCR effect. The valence change of Mn ions was explained by vanishing of the Jahn‐Teller effect as the phase changes from tetragonal to cubic.

Original language	English
Pages (from-to)	2845-2848
Number of pages	4
Journal	Journal of the American Ceramic Society
Volume	78
Issue number	10
DOIs	https://doi.org/10.1111/j.1151-2916.1995.tb08065.x
State	Published - Oct 1995

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10.1111/j.1151-2916.1995.tb08065.x

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title = "Valence Change of Mn Ions in BaTiO3‐Based PTCR Materials",

abstract = "The effect of Mn on the PTCR characteristics of La‐doped BaTiO3 ceramics was studied. Acceptor state density was measured from a p‐1/T graph as a function of Mn concentration. The behavior of room‐temperature resistivity with Mn concentration was explained by compensation of acceptors at grain boundaries. The valence state of Mn was analyzed by ESR, and it changed near the Curie temperature of BaTiO3 from 3+ in tetragonal phase to 2+ in cubic phase. Therefore, the number of electron traps increased at the Curie temperature, leading to the great improvement in the PTCR effect. The valence change of Mn ions was explained by vanishing of the Jahn‐Teller effect as the phase changes from tetragonal to cubic.",

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T1 - Valence Change of Mn Ions in BaTiO3‐Based PTCR Materials

AU - Lee, Joon‐Hyung ‐H

AU - Kim, Sung‐Hee ‐H

AU - Cho, Sang‐Hee ‐H

PY - 1995/10

Y1 - 1995/10

N2 - The effect of Mn on the PTCR characteristics of La‐doped BaTiO3 ceramics was studied. Acceptor state density was measured from a p‐1/T graph as a function of Mn concentration. The behavior of room‐temperature resistivity with Mn concentration was explained by compensation of acceptors at grain boundaries. The valence state of Mn was analyzed by ESR, and it changed near the Curie temperature of BaTiO3 from 3+ in tetragonal phase to 2+ in cubic phase. Therefore, the number of electron traps increased at the Curie temperature, leading to the great improvement in the PTCR effect. The valence change of Mn ions was explained by vanishing of the Jahn‐Teller effect as the phase changes from tetragonal to cubic.

AB - The effect of Mn on the PTCR characteristics of La‐doped BaTiO3 ceramics was studied. Acceptor state density was measured from a p‐1/T graph as a function of Mn concentration. The behavior of room‐temperature resistivity with Mn concentration was explained by compensation of acceptors at grain boundaries. The valence state of Mn was analyzed by ESR, and it changed near the Curie temperature of BaTiO3 from 3+ in tetragonal phase to 2+ in cubic phase. Therefore, the number of electron traps increased at the Curie temperature, leading to the great improvement in the PTCR effect. The valence change of Mn ions was explained by vanishing of the Jahn‐Teller effect as the phase changes from tetragonal to cubic.

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DO - 10.1111/j.1151-2916.1995.tb08065.x

M3 - Article

AN - SCOPUS:0029389168

SN - 0002-7820

VL - 78

SP - 2845

EP - 2848

JO - Journal of the American Ceramic Society

JF - Journal of the American Ceramic Society

IS - 10

ER -

Valence Change of Mn Ions in BaTiO₃‐Based PTCR Materials

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