The melt-spun ribbons of nominal composition Pr_(9)Fe_(84.2-x)B_(6.2)P_(0.3)Zr_(0.3)Cu_(x)(x=0,0.5,1,2)were prepared at wheel speeds of 21 m·s^(-1),27 m·s^(-1),30 m·s^(-1),and 33 m·s^(-1).The XRD p...The melt-spun ribbons of nominal composition Pr_(9)Fe_(84.2-x)B_(6.2)P_(0.3)Zr_(0.3)Cu_(x)(x=0,0.5,1,2)were prepared at wheel speeds of 21 m·s^(-1),27 m·s^(-1),30 m·s^(-1),and 33 m·s^(-1).The XRD patterns show that as the wheel speed increases,the crystallinity of the 2:14:1 hard phase decreases,while that of theα-Fe soft phase increases.The(BH)_(max),remanence,and coercivity are improved from 63 kJ·m^(-3),0.85 T,and 515 kA·m^(-1)for the Cu-free ribbons to 171 kJ·m^(-3),1.08 T,and684 kA·m^(-1)with x=0.5.The high squareness ratio of J_(r)/J_(s)~0.82 at 0.5 at.%Cu(27 m·s^(-1))indicates strong exchange coupling due to small grain sizes of 15 nm and 30 nm for soft and hard magnetic phases,respectively.The SEM images revealed smooth morphology and uniform element distribution at 0.5 at.%Cu(27 m·s^(-1)),contributing to the high magnetic properties.The low recoil permeability(μrec)value of 5.466×10^(-4)T/kA·m^(-1)to 1.970×10^(-4)T/kA·m^(-1)confirms the strong exchange coupling with x=0.5(27m·s^(-1)).The initial magnetization curves show that the coercivity mechanism of the Cu-free alloy evolves from the nucleation of the reverse domain to the domain wall pinning as the wheel speed increases,resulting in a high coercivity value of 818 kA·m^(-1)(33 m·s^(-1)).Conversely,for the Cu-added alloy,the coercivity mechanism changes from pinning to the nucleation of the reverse domain from low to high wheel speed.展开更多
The magnetization-direction-dependent inverse spin Hall effect(ISHE) has been observed in NiFe film during spin Seebeck measurement in IrMn/NiFe/Cu/yttrium iron garnet(YIG) multilayer structure, where the YIG and NiFe...The magnetization-direction-dependent inverse spin Hall effect(ISHE) has been observed in NiFe film during spin Seebeck measurement in IrMn/NiFe/Cu/yttrium iron garnet(YIG) multilayer structure, where the YIG and NiFe layers act as the spin injector and spin current detector, respectively. By using the NiFe/IrMn exchange bias structure, the magnetization direction of YIG(MYIG) can be rotated with respect to that of NiFe(MNiFe) with a small magnetic field, thus allowing us to observe the magnetization-direction-dependent inverse spin Hall effect voltage in NiFe layer. Compared with the situation that polarization direction of spin current(σs) is perpendicular to MNiFe, the spin Seebeck voltage is about 30% larger than that when σs and MNiFe are parallel to each other. This phenomenon may originate from either or both of stronger interface or bulk scattering to spin current when σs and MNiFe are perpendicular to each other. Our work provides a way to control the voltage induced by ISHE in ferromagnets.展开更多
The spin transparency at the normal/ferromagnetic metal （NM/FM） interface was studied in PffYIG/Cu/FM multilayers. The spin current generated by the spin Hall effect （SHE） in Pt flows into Cu/FM due to magnetic in...The spin transparency at the normal/ferromagnetic metal （NM/FM） interface was studied in PffYIG/Cu/FM multilayers. The spin current generated by the spin Hall effect （SHE） in Pt flows into Cu/FM due to magnetic insulator YIG blocking charge current and transmitting spin current via the magnon current. Therefore, the nonlocal voltage induced by an inverse spin Hall effect （ISHE） in FM can be detected. With the magnetization of FM parallel or antiparallel to the spin polarization of pure spin currents （σsc）, the spin-independent nonlocal voltage is induced. This indicates that the spin transparency at the Cu/FM interface is spin-independent, which demonstrates that the influence of spin-dependent electro-chemical potential due to spin accumulation on the interfacial spin transparency is negligible. Furthermore, a larger spin Hall angle of Fe20Ni80 （Py） than that of Ni is obtained from the nonlocal voltage measurements.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12074220 and 11627805)the National Key Research and Development Program of China(Grant No.2023YFA1406604)。
文摘The melt-spun ribbons of nominal composition Pr_(9)Fe_(84.2-x)B_(6.2)P_(0.3)Zr_(0.3)Cu_(x)(x=0,0.5,1,2)were prepared at wheel speeds of 21 m·s^(-1),27 m·s^(-1),30 m·s^(-1),and 33 m·s^(-1).The XRD patterns show that as the wheel speed increases,the crystallinity of the 2:14:1 hard phase decreases,while that of theα-Fe soft phase increases.The(BH)_(max),remanence,and coercivity are improved from 63 kJ·m^(-3),0.85 T,and 515 kA·m^(-1)for the Cu-free ribbons to 171 kJ·m^(-3),1.08 T,and684 kA·m^(-1)with x=0.5.The high squareness ratio of J_(r)/J_(s)~0.82 at 0.5 at.%Cu(27 m·s^(-1))indicates strong exchange coupling due to small grain sizes of 15 nm and 30 nm for soft and hard magnetic phases,respectively.The SEM images revealed smooth morphology and uniform element distribution at 0.5 at.%Cu(27 m·s^(-1)),contributing to the high magnetic properties.The low recoil permeability(μrec)value of 5.466×10^(-4)T/kA·m^(-1)to 1.970×10^(-4)T/kA·m^(-1)confirms the strong exchange coupling with x=0.5(27m·s^(-1)).The initial magnetization curves show that the coercivity mechanism of the Cu-free alloy evolves from the nucleation of the reverse domain to the domain wall pinning as the wheel speed increases,resulting in a high coercivity value of 818 kA·m^(-1)(33 m·s^(-1)).Conversely,for the Cu-added alloy,the coercivity mechanism changes from pinning to the nucleation of the reverse domain from low to high wheel speed.
基金supported by the National Basic Research Program of China(Grant No.2015CB921502)the National Natural Science Foundation of China(Grant Nos.11474184 and 11627805)+1 种基金the 111 Project,China(Grant No.B13029)the Fundamental Research Funds of Shandong University,China
文摘The magnetization-direction-dependent inverse spin Hall effect(ISHE) has been observed in NiFe film during spin Seebeck measurement in IrMn/NiFe/Cu/yttrium iron garnet(YIG) multilayer structure, where the YIG and NiFe layers act as the spin injector and spin current detector, respectively. By using the NiFe/IrMn exchange bias structure, the magnetization direction of YIG(MYIG) can be rotated with respect to that of NiFe(MNiFe) with a small magnetic field, thus allowing us to observe the magnetization-direction-dependent inverse spin Hall effect voltage in NiFe layer. Compared with the situation that polarization direction of spin current(σs) is perpendicular to MNiFe, the spin Seebeck voltage is about 30% larger than that when σs and MNiFe are parallel to each other. This phenomenon may originate from either or both of stronger interface or bulk scattering to spin current when σs and MNiFe are perpendicular to each other. Our work provides a way to control the voltage induced by ISHE in ferromagnets.
基金Project supported by the National Basic Research Program of China(Grant No.2015CB921502)the National Natural Science Foundation of China(Grant Nos.11474184 and 11627805)+1 种基金the 111 Project,China(Grant No.B13029)the Fundamental Research Funds of Shandong University,China
文摘The spin transparency at the normal/ferromagnetic metal （NM/FM） interface was studied in PffYIG/Cu/FM multilayers. The spin current generated by the spin Hall effect （SHE） in Pt flows into Cu/FM due to magnetic insulator YIG blocking charge current and transmitting spin current via the magnon current. Therefore, the nonlocal voltage induced by an inverse spin Hall effect （ISHE） in FM can be detected. With the magnetization of FM parallel or antiparallel to the spin polarization of pure spin currents （σsc）, the spin-independent nonlocal voltage is induced. This indicates that the spin transparency at the Cu/FM interface is spin-independent, which demonstrates that the influence of spin-dependent electro-chemical potential due to spin accumulation on the interfacial spin transparency is negligible. Furthermore, a larger spin Hall angle of Fe20Ni80 （Py） than that of Ni is obtained from the nonlocal voltage measurements.
