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A Study of the Effects of Small Amount of Eu Impurities in α-Fe2O3

α-Fe2O3 에 첨가한 미소량 EU 불순물의 효과에 대한 연구

  • 오창헌 (연세대학교 초미세표면과학연구소)
  • Published : 2003.06.01

Abstract

Crystallographic, electric, magnetic and heat transition properties of $\alpha$-Fe$_2$O$_3$ have been studied with a small addition of Eu impurities. Hematite($\alpha$-Fe$_2$O$_3$) is a basic ferromagnetic material having rhombohedral structure, which is similar to perovskites structure. Eu is a rare earth element that has an electric configuration of 4f$^{7}$ 6s$^2$. X-ray diffraction pattern of Fe$_{1-x}$ Eu$_{x}$O$_3$ (x = 0.00, 0.04, 0.06) shows an increament of a value when the amount of Eu impurities increased. The VSM data show an increment of magnetization by increasing the amount of Eu impurity. The one with x=0.06 shows the largest increment of magnetic remanence. The magnetic remanence varied from 0.49$\times$10$^{-3}$ emu/g to 0.62$\times$10$^{-3}$ emu/g when Eu impurity is increased by 2 %. Coercivity is decreased as Eu impurity is increased. Resistances is reduced significantly by Eu impurity. There is a clear difference in temperature-dependent resistance depending on the amount of Eu impurities. Especially, there are cusps between 150 K to 175 K. It indicates the change of electronic quantum states inside the atoms by rare earth impurities in rhombohedral structure. Temperature-dependent heat capacity shows that the most effective amount of Eu impurities is 6 %. %.

References

  1. 전기전자재료학회논문지 v.12 no.2 PECVD 법에 의한 가스센서용 다공성 $α-Fe_{2}O_{3}$ 박막제조 이은태;장건익;정용선
  2. Proc. 5th ICPADM Photoelectrochemical Characterization of GaAs and Doped $Fe_{2}O_{3}$ Semiconductive Electrodes Il-Kwang;Seung-Il Jeong;Gi-Su Oh;Chung-Sik Shin;Tae-Young Park
  3. 한국전기전자재료학회 1989년 춘계학술대회논문집 $Fe_{2}O_{3}$계 NTC thermistor의 첨가물 영향 강희복;이동희;김상영;한성진;성영권
  4. Phys. Rev. v.78 Magnetic Susceptibility of $αFe_{2}O_{3}$ and $αFe_{2}O_{3}$ with added titanium F.J.Morin
  5. Powder Diffraction File JCPDS
  6. Sing. J. Phys. v.8 The Spin-flip transition in the system of $(Fe_{2}O_{3})_{1-x}(In_{2}O_{3})_{x}$ J.G.Kim;Y.J.Kim;Y.K.Hong