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Journal of the Korean Chemical Society (JKCS)

ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 35, Number 3
JKCSEZ 35(3)
June 20, 1991 

Nonstoichiometry and Magnetic Property of the Nd1-xSrxCoO3-y System

Nd1-xSrxCoO3-y계의 비화학양론 및 자기적 특성
Chul Hyun Yo, Kwon Sun Roh, Sung Joo Lee, Kyu Hong Kim, Eung Ju Oh

여철현, 노권선, 이성주, 김규홍, 오응주
Nd1-xSrxCoO3-y계(x = 0.00, 0.25, 0.50, 0.75 및 1.00)의 시료들을 1200℃, 대기압하에서 제조하였다. 제조된 고용체들을 X-선 회절, 열분석, 전자현미경 마이크로그래프로 분석한다. X-선 회절분석에 의하면 조성이 x = 0.00, 0.25, 0.50 및 0.75인 시료는 입방정계이고, x = 1.00인 시료는 사방정계이다. 이 계에서 환산 격자부피는 x값이 증가함에 따라 증가한다. Co4+의 몰비인 τ값은 요오드 적정법으로 결정하고, x = 0.50에서 최대값을 갖는다. 자기측정에 의하면 조성이 x = 0.00, 0.25, 0.50 및 0.75에서는 강자성이 나타나고 x = 1.00에서는 반강자성이 나타난다. 전기전도도 측정에 의하면 x = 0.00, 0.25 및 1.00에서는 반도성을 나타내고 x = 0.50 및 0.75에서는 금속성을 나타낸다. 시료들의 자기적 성질들을 비화학양론적 조성식과 관련시켜 논의하였다.

A series of samples in the Nd1-xSrxCoO3-y system (x = 0.00, 0.25, 0.50, 0.75 and 1.00) have been produced by heating the reactants at 1200℃ under atmospheric pressure. The solid solutions were analysed by X-ray diffraction spectra, thermal analysis, and SEM micrographs. X-ray powder diffraction assigns the compositions of x = 0.00, 0.25, 0.50 and 0.75 to the cubic system and the composition of x = 1.00 to the orthorhombic system. The reduced lattice volume is increased with increasing x values in the system. The mole ratio of Co4+ or τ values are determined by the Iodometric titration method and are maximum at the composition of x = 0.50. The magnetic measurement shows that a ferromagnetism is appeared in the compositions of x = 0.00, 0.25, 0.50 and 0.75 and then an antiferromagnetism in the composition of x = 1.00. The measurement of the electrical conductivity shows that the semiconductivity is appeared in the composition of x = 0.00, 0.25 and 1.00 and the metallic conductivity in the composition of x = 0.50 and 0.75. The magnetic and electrical properties of the samples are discussed with the nonstoichiometric chemical formulas.

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