http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
ThMn₁₂형 NdFe10.7Ti1.2Mo0.1의 미세구조 및 자기적 성질 연구
안성용(Sung Yong An),이승화(Seung Wha Lee),김철성(Chul Sung Kim),김윤배(Y. B. Kim),김창석(C. S. Kim) 한국자기학회 1997 韓國磁氣學會誌 Vol.7 No.2
We have studied crystallographic and magnetic properties of NdFe_(10.7)Ti_(1.2)Mo_(0.1) by Mossbauer spectroscopy, X-ray diffraction and vibrating sample magnetometer(VSM). The alloys were prepared by arc-melting under an argon atmosphere. The NdFe_(10.7)Ti_(1.2)Mo_(0.1) has pure a single phase, whereas NdFe_(10.7)Ti_(1.3) contains some α-Fe, conformed with X-ray diffractometry and Mossbauer measurements. The NdFe_(10.7)Ti_(1.2)Mo_(0.1) has a ThMn₁₂-type tetragonal structure with a_0=8.637Å and c_0=4.807Å. The Curie temperature (Tc) is 600 K from the result of Mossbauer measurement performed at various temperatures ranging from 13 to 800 K. Each spectrum of below Tc is fitted with five subspectra of Fe sites in the structure (8i₁, 8i₂, 8j₂, 8j₁, 8f). The area fractions of the subspectra at room temperature are 12.3%, 14.0%, 21.0%, 11.8%, 40.9%, respectively. Magnetic hyperfine fields for the Fe sites decrease in the order, Hhf(8i)>Hhf(8j)>Hhf(8f). The abrupt changes in the magnetic hyperfine field, an magnetic moment observed at about 160 K in NdFe_(10.7)Ti_(1.2)Mo_(0.1) are attributed to spin reorientations. The average hyperfine field of the NdFe_(10.7)Ti_(1.2)Mo_(0.1) shows a temperature dependence of [Hhf(T)-Hhf(0)]/Hhf(0) = -0.34(T/Tc)((3/2)-0.14(T/Tc)^(5/2) for T/Tc<0.7, indicative of spin wave excitation. The Debye temperatures of NdFe_(10.7)Ti_(1.2)Mo_(0.1) is found to be Θ = 340±5 K.
Nd - Fe - Ti - B 비정질 합금의 자기적 성질 연구
이승화(Seung Wha Lee),안성용(Sung Yong An),김철성(Chul Sung Kim),김윤배(Y. B. Kim),김창석(C. S. Kim) 한국자기학회 1997 韓國磁氣學會誌 Vol.7 No.3
The amorphous state of NdFe_(10.7)TiB_(0.3) and its nanocrystallization have been studied by X-ray diffraction, Mossbauer spectroscopy, and a vibrating sample magnetometer(VSM). NdFe_(10.7)TiB_(0.3) amorphous ribbons were fabricated by a single-roll melt-spinning method. The average hyperfine field Hhf (T) of the amorphous state shows a temperature dependence of [Hhf(T)-Hhf(0)]/Hhf(0)=-0.46(T/T_C)^(3/2) -0.34(T/T_C)^(5/2) for T/T_C < 0.7, indicative of spin wave excitation. The quadrupole splitting just above the Curie temperature T_C is 0.46 ㎜/s, whereas the average quadrupole shift below T_C is zero. The Curie and crystallization temperatures are determined to be T_C=380 K and T_X=490 K, respectively, for a heating rate of 5 K/min. The occupied area of nanocrystalline phase at around 770 K is about 65 %. Above the Curie temperature, VSM data show magnetic moments increase again. The formation of α-Fe is the main reason for the increasing moment as conformed with the Mossbauer measurements.
NdFe10.7Ti1.3의 결정학적 및 자기적 성질 연구
이승화(Seung Wha Lee),이용종(Young Jong Lee),안성용(Sung Yong An),김철성(Chul Sung Kim),김윤배(Y. B. Kim),김창석(C. S. Kim) 한국자기학회 1996 韓國磁氣學會誌 Vol.6 No.6
NdFe_(10.7)Ti_(1.3) has been studied with X-ray diffraction, Mossbauer spectroscopy and vibrating sample magnetometer(VSM). The alloys were prepared by arc-melting under an argon atmosphere. The NdFe_(10.7)Ti_(1.3) contains some α-Fe, from X-ray and Mossbauer measurements. The NdFe_(10.7)Ti_(1.3) has the ThMn₁₂-type tetragonal structure with α_0=8.607 Å and c_0=4.790 Å. The Curie temperature(Tc) of the NdFe_(10.7)Ti_(1.3) is 590 K from Mossbauer spectroscopy performed at various temperatures ranging from 13 to 800 K. Each spectrum below Tc was fitted with six subspectra of Fe sites in the structure(8i₁, 8i₂, 8j₂, 8j₁, 8f and α-Fe). The area fractions of the subspectra at room temperature are 13.8 %, 15.4 %, 17 %, 16.4 %, 34.1 % and 3.3 %, respectively. Magenetic hyperfine fields for the Fe sites decrease in the order, Hhf(8i)>Hhf(8j)>Hhf(8f). The abrupt changes in the magnetic hyperfine field, isomer shift and magnetic moment observed at about 180 K in NdFe_(10.7)Ti_(1.3) are attributed to spin reorientation.