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1、第42卷第6期 2013年11月 内蒙古师范大学学报(自然科学汉文版) Journal of Inner Mongolia Normal University(Natural Science Edition) Vol_42 No6 Nov2013 Structural and Magnetic Properties of YzCo1524一 Fe Cr176 Compounds BHuliyageqi ，0Tegus ，NING Jun ，BFuquan (1_Inner Mongolia Key Laboratory for Physics and Chemistry of Function
2、al Materials，Inner Mongolia Normal University： 2College of Physics and Electronic Information，Inner Mongolia Normal University，Hohhot 010022，China) Abstract：The structural and magnetic properties of Y2Col524一 FaxCr176 compounds have been investigated in the concentration region 2x8The powder X-ray d
3、iffraction patterns at room temperature show that all of the compounds crystallize in the Th2 Nil7-type structureThe lattice parameters a，c and the unit eell volume V inerease monotonically with increasing Fe contentThe Xray diffraction patterns of the magnetically aligned samples show that the comp
4、ounds with z一26 exhibit uniaxial anisotropy。but the compound with z一8 has a planar anisotro PYThe spin reorientation phenomena occurs only in the compound with 一8The Curie temperature Tc decreases with increasing Fe contentsThe saturation magnetization of the compounds decreases with increasing temp
5、era ture，and increases with Fe contentsThe anisotropy field B and the anisotropy constant K1 of the compounds presented the maximum value at 一6 Key words：rare earth-intermetallic compounds；spin reorientation；uniaxial anisotropy；planar anisotropy CLC number：0 48251 Document code：A Article ID：1001-873
6、5(2013)06-0649-05 R2 T1 7 type rareearth(R)transitionmetal(T)compounds(T：Fe or Co)have been attracting much attention due to possible practical applications of these compounds as high energy-product magnetsThe binary R2Co17(Rrare earth element)compound exhibits a weak uniaxial anisotropy，while R2Fe1
7、7 exhibits a planar anisotropy Recent studies have shown that the substitution of FeCo in R2T”(TFe or Co)by proper elements，such as AI，Ga and Si，offers the possibility of the preferred site occupations in the crystal structure，and has a pronounced influence on the magnetic anisotropy of the compound
8、s。 Fuquan et alE。 reported that the crystal structure of the Y2 Co17Cr compounds could be transformed from Th2 Zn17一type for x2 to Th2 Nil7一type for x2In order to understand the origin of the magnetic anisotropy and to optimize the magnetic properties of the compounds，a further systematic investigat
9、ion of the influence of the substitution elements and their contents on the crystal structure and on the magnetic properties of Rz T17一type compounds is still neededIn this paper，the structural and magnetic properties of the Y2 Col524Fe C 176( 一28)compounds are presented 1 Experimental The ingots of
10、 Y2 Co1524一 Fe Cr176( 一28)compounds were prepared by arc melting the starting elements with purity of at least 999 0AThen the ingots were wrapped molybdenum foil and sealed in quartz tubes with an Ar atmosphere of 100 mbar，and annealed at 1 373 K for 72 h，and then quenched in water rapidlyX-ray diff
11、raction(XRD)with CuK radiation was used for the determination of the crystal structure，the lattice parameters，and the anisotropy type of the compoundsIn order to obtain the samples Received date：20130305 Foundation item：Project Supported by the National Science Foundation(2O1OMS01O4) Biography：BHuli
12、yageqi(1956一)，Male(Mongolian) Natural Science Foundation of China(51161017)and the Inner Mongolia Natural ，Associate Professor of Inner Mongolia Normal University 650 内蒙古师范大学学报(自然科学汉文版) 第42卷 for XRD measurements，the fine powder of each compound was mixed with epoxy resin and filled into a plastic tu
13、be of 20 mm2 mm and placed it into an external field of about 10 T with its vertical axis parallel to the field direction until the epoxy resin was solidifiedFor the compound with z一8，the sample was mounted on a motor to rotate around its vertical axis perpendicular to same applied field The thermom
14、agnetic curves were measured in a field of 5 0 mT by using aLakeshore 7 40 7 Vibrating Sample Magnetometer(VSM)in the temperature range from liquid nitrogen temperature to above the Curie temperature of the compoundsThe magnetization along the easy magnetization direction(EMD)and hard magnetization
15、direction(HMD)of the aligned samples was measured with a SQUID magnetometer (Quantum Design MPMS5)in applied fields up to 5 T at 5 K，105 K，205 K and 305 KIn order to prepare the samples for SQUID measurements，the fine powder of each sample was mixed with epoxy resin and filled into two plastic tubes
16、 with 3 mm8 mm cylindrical shapeOne of them w8s placed into an external field of about 10 T with its axis parallel to the field direction and the other one was mounted on a motor to rotate the mode around its vertical axis perpendicular to the same applied field until the epoxy resin was solidified The values of saturation magnetization M at 5 K，105 K，205 K and 305 K were derived from the M1B curves by extrapolating 1
