HOME > Profile > HASE, Masashi
- Address
- 305-0047 1-2-1 Sengen Tsukuba Ibaraki JAPAN [Access]
Research
- Keywords
Antiferromagnetic materials; Inelastic neutron scattering; Magnetization; Parameter estimation; Quantum theory
In this paper,we could not reproduce well the experimental susceptibility and magnetization by our calculation technique. Accordingly,it is necessary to calculate susceptibility and magnetization of the competing system with J1, J2, and extra interactions in the case that 20 =< N and to evaluate susceptibility and magnetization of the infinit chains.
Phys Rev B 73 (2006) 104419.
PublicationsNIMS affiliated publications since 2004.
Society memberships
日本物理学会, 日本中性子科学会
Awards
- 富山県未来財団 富山賞（1995年），日本金属学会 奨励賞（1998年） ()
Research Center for Materials Nanoarchitectonics (MANA)
Title
Research on Magnetic Materials Using Neutron Diffraction under an Applied Magnetic Field
Keywords
neutron diffraction, magnetic field, magnetic material, quantum spin system, quantum material
Overview
In neutron diffraction, magnetic structures (the arrangements of magnetic moments) can be investigated, but conventional neutron diffraction cannot be applied to the paramagnetic state, in which the magnetic moments are not ordered. When a magnetic field is applied to a paramagnetic state, field-induced magnetic moments appear parallel to the applied field, producing magnetic Bragg peaks. By analyzing these magnetic Bragg peaks, the field-induced magnetic moment at each site can be determined. By combining this information with other experimental results, such as magnetization and specific-heat measurements, we can obtain more accurate information about the magnetic interactions within the material. This can contribute to the development of magnetic materials. To date, we have successfully demonstrated the direct observation of eigenstates in quantum mechanics and the determination of magnetic models.
Novelty and originality
It enables us to obtain information about the paramagnetic state that could not be accessed by conventional neutron diffraction.
By applying the magnetic field perpendicular to the neutron scattering vector, the sensitivity can be enhanced by approximately a factor of four.
It enables us to obtain more accurate information about the magnetic interactions within the material. Conventional methods based on magnetization and specific-heat measurements have the limitation that the magnetic interactions cannot always be determined uniquely.
Details
We present an example of applying this method to the quantum spin system Ni2V2O7. The left figure shows the magnetic structures in zero magnetic field. Two successive magnetic transitions occur at TN1=6.7 K and TN2=5.7 K. At 6.0 K, between TN1 and TN2, only the Ni2 moments of the two types of Ni moments become ordered, resulting in a spin-density-wave structure. At 2.3 K, below TN2, both types of Ni moments become ordered, giving rise to an elliptical cycloidal structure.
To understand such complex magnetic structures, it is important to obtain accurate information on the magnetic interactions. We therefore performed neutron diffraction measurements under a magnetic field. This experiment takes advantage of the fact that this material becomes paramagnetic when a magnetic field of more than 80,000 gauss is applied. The results are shown in the right figure. At a magnetic field of 100,000 gauss, the field-induced moments of Ni1 and Ni2 were found to be 0.3 and 1.9 muB (Bohr magnetons), respectively. These results are consistent with the dimer–monomer model proposed in previous studies.
Summary
Because it enables more accurate acquisition of information on magnetic interactions within materials than conventional methods, it can contribute to the research and development of magnetic materials, quantum materials, quantum liquid-crystal materials, and other related materials.
この機能は所内限定です。
この機能は所内限定です。