RESEARCH ON NEW GIANT MAGNETOSTRICTIVE RARE EARTH-TRANSITION METAL INTERMETALLIC COMPOUNDS, AND CONTROL OF HIGH MAGNETOMECHANICAL COUPLING

从物理角度对新型超磁致伸缩材料进行了研究，并开展了实现高磁力耦合的开发工作新型超磁致伸缩化合物的研究（1-1）RCo_3化合物RCo_3在室温下对R=Y、Pr、Sm、Gd、Tb和Dy的磁致伸缩量分别为-25x10^<-6>、-155x10^<-6>、-65x10^<-6>、760x10^<-6>、80x10^<-6>。在77K时，TbCo_3的磁致伸缩量达到2680x10^<-6>，与典型的巨磁致伸缩化合物TbFe_2相当。（1-2） Tb(Fe_<1-x>M_x)_2化合物：将M元素（M=Co, Ni, Mn, Cr, Ti， V）取代TbFe_2中的Fe位，导致磁致伸缩降低。通过形成纳米晶和非晶相，制备出具有高磁力耦合的超磁致伸缩材料（2-1）TbFe_2化合物快速淬火，淬火速度从8m/s提高到32m/s，晶粒尺寸从400A减小到250A，矫顽力降至9000e。这表明，与软磁材料类似，巨磁致伸缩化合物的纳米晶的形成可以抑制磁晶的各向异性。另一方面，Fe_2Tb的非晶化不能获得高磁弹性耦合。（2-2） Sm_<1-x>Fe_x体系在x=0.66左右形成SmFe_2化合物dmgcu_2相的快速淬火。Sm_<0.34>Fe_<0.66>的磁致伸缩小于-500x10^<-6>，而Sm_<0.35>(Fe_<0.5>Co_<0.5>)_<0.65>的磁致伸缩达到-1100x10^<-6>。在快速淬火的SmFe体系中没有获得磁性柔软度。（2-3）动态磁-力耦合测量装置该装置由偏置磁场、交流励磁场、阻抗分析仪和用于系统控制和数据分析的个人计算机组成。对于L/D大于15的薄带材，动态磁力耦合的测量精度在5%以内。少

Research work on new giant magnetostrictive materials from a physical view point and a development work to attain high magnetomechanical coupling were carried out.[1] Research on new giant magnetostrictive compounds(1-1) RCo_3 compoundMagnetostriction of RCo_3 at room temperature is -25x10^<-6>, -155x10^<-6>, -65x10^<-6>, 760x10^<-6>, 80x10^<-6> for R=Y, Pr, Sm, Gd, Tb and Dy, respectively. The magnetostriction of TbCo_3 reaches 2680x10^<-6> at 77K, which is comparable to the typical giant magnetostrictive compound TbFe_2.(1-2) Tb(Fe_<1-x>M_x)_2 compoundA substitution of M elements (M=Co, Ni, Mn, Cr, Ti, V) to the Fe site in TbFe_2 causes a reduction of magnetostriction. However it improves a magnetic softness in the case of M=Ti, Cr, Mn and Co.[2] Development of the giant magnetostrictive materials with a high magnetomechanical coupling by forming nanocrystallite and amorphous phase(2-1) Rapidly quenching of TbFe_2 compoundAs a quenching velocity increases from 8m/s to 32m/s, the crys … More talline size decreases from 400A to 250A and the coercive force drops to 9000e. This indicates that a magnetocrystalline anisotropy can be suppressed by a formation of nanocrystalline of giant magnetostrictive compounds similarly to soft magnetic materials. On the other hand, a high magnetoelastic coupling was not attained by an amorphization of Fe_2Tb.(2-2) Rapidly quenching of SmFe_2 compoundMgCu_2 phase is formed in the Sm_<1-x>Fe_x system around x=0.66. The magnetostriction is less than -500x10^<-6> for Sm_<0.34>Fe_<0.66>, but reaches -1100x10^<-6> for Sm_<0.35>(Fe_<0.5>Co_<0.5>)_<0.65>. The magnetic softness was not obtained in a rapidly quenched SmFe system.(2-3) Measurement apparatus for dynamic magnetomechanical couplingThe apparatus is composed of bias magnetic field, ac exciting field, impedance analyzer and personal computer for system control and data analysis. A dynamic magnetomechanical coupling for thin ribbons having L/D more than 15 can be measured in the accuracy within 5%. Less