Cr-Al-V合金的电输运和热膨胀  

ELECTRICAL TRANSPORT AND THERMAL EXPANSION IN Cr-Al-V ALLOY

作　　者：魏义永[1] 高惠平[1] 李波[1] 吴柏枚[1] 

机构地区：[1]中国科学技术大学物理系

出　　处：《低温物理学报》2007年第2期145-148,共4页Low Temperature Physical Letters

基　　金：国家自然科学基金(项目编号:10174070)资助的课题~~

摘　　要：本文报道了Cr97.02Al2.98和掺钒的(Cr98.26Al1.74)98.72V1.28、(Cr96.04Al3.96)98.69V1.31合金在10～450K温区的电阻率和热膨胀系数随温度的变化.随着温度降低,Cr97.02Al2.98合金经历了顺磁-公度自旋密度波(CSDW)-非公度自旋密度波(ISDW)的转变.Neel温度以下电阻率出现上升趋势,与SDW反铁磁能隙的逐渐打开有关.热膨胀-温度曲线在Neel温度附近呈现一个明显的跳跃行为,是磁转变相关的磁体效应.低于CSDW-ISDW转变温度,电阻率的增大是由于磁散射在低温下增强.用公式ρ=ρ0+AlnT+BT2+CT5对三个合金10～80K温区内电阻率-温度曲线的拟合结果表明,随着钒掺杂的增加,磁散射和s～d电子散射减小.Cr97.02Al2.98合金中掺入少量钒就能压制SDW.Electrical resistivity ρ （T） and thermal expansion α （T） have been measured in the temperature range of 10 - 450 K for Cr97.02 Al2.98, （ Cr98.26 Al1.74 ）98.72 V1.28 and （ Cr96.04 Al3.96 ）98.69 V1.31 alloys. As temperature decreases, paramagnetic-commensurate spin density wave （CSDW）-incommensurate spin density wave（ISDW） transition occurs in the Cr97.02Al2.98 alloy. The upward bend below the Neel temperature （TN） in ρ（T） curve is associated with the progressive opening up of the energy gap in the Cr97.02Al2.98 alloy, The α（T） curve for the Cr97.02Al2.98 alloy displays an obvious jumplike behavior near TN, which is the magnetovolume effect related to the magnetic transition. The increase in of the Cr97.02 Al2.98 alloy below TIC is due to the magnetic scattering becomes strong with decreasing temperature. In the temperature range 10 -80 K, the experimental data of ρ（T） for three compounds are fitted fairly well by Eq. ρ =ρo ＋ AlnT ＋ BT^2 ＋ CT^5. Results indicate the magnetic scattering and the electron s - d scattering are weakened with the V doping increasing. The SDW is suppressed by doping V in the Cr97.02Al2.98 alloy.

关 键 词：热膨胀 电阻率 自旋密度波 CrAlV合金 

分 类 号：O482[理学—固体物理]