SPring-8, the large synchrotron radiation facility

Skip to content
» JAPANESE
Personal tools
 

Mechanism of spontaneous lattice distortion to stabilize ferromagnetic state in metals -Clarification of the mechanism behind magnetism appearing in ultrathin metal films expected-(Press Release)

Release Date
22 Jun, 2018
  • BL13XU (Surface and Interface Structures)

June 22, 2018
Japan Synchrotron Radiation Research Institute (JASRI)

Key points
• Spontaneous distortion upon the appearance of ferromagnetism in ultrathin metal films was directly observed by surface X-ray diffractometry.
• A close relationship among lattice distortion, the quantum-well state, and the appearance of magnetism was clarified, leading to the development of magnetic switching using distortion.

A research group consisting of Shunsuke Sakuragi (completed Ph.D. course in March 2017, currently a project researcher at the Institute for Solid State Physics of The University of Tokyo) and Tetsuya Sato (professor) of the Faculty of Science of Keio University, Hiroo Tajiri (research scientist) of JASRI, and Hiroyuki Kageshima (professor) at the Graduate School of Natural Science and Technology of Shimane University carried out surface X-ray diffractometry of ultrathin Pd films using the SPring-8 BL13XU beamline and clarified the mechanism of spontaneous lattice distortion to stabilize the ferromagnetic state in Pd ultrathin films. In addition, the group found a new crystal growth mode. Concretely, the energy gain via lattice expansion from the appearance of ferromagnetism in Pd results in the growth of flat and uniform ferromagnetic ultrathin Pd films. From the above findings, lattice distortion was found to be closely related to the appearance of magnetism, leading to the possibility of the development of magnetic switching devices using distortion.

The achievements of this study were published online on 18 June 2018 (Eastern time, USA) in Physical Review B.

Reference:
Journal: Physical Review B
Title: Spontaneous distortion via the appearance of ferromagnetism in Pd ultrathin films: Observation of an inverse mechanism for the Stoner criterion
Authors: Shunsuke Sakuragi,1 Hiroo Tajiri,2 Hiroyuki Kageshima,3 and Tetsuya Sato1
Affiliations: 1 Department of Applied Physics and Physico-Informatics, Keio University, 2 Japan synchrotron Radiation Research Institute/SPring-8, 3 Interdisciplinary Graduate School of Science and Engineering, Shimane University
DOI: 10.1103/PhysRevB.97.214421
Fig. 1

Fig. 1 (a) X-ray reflectivities of ultrathin Pd(100) films. (b) Relationship between magnetic moment and uniformity of crystallinity. The magnetic moment and the uniformity of crystallinity periodically increase with the thickness of Pd ultrathin films.

Fig. 2

Fig. 2 (a) Relationship between distribution of thickness and magnetism in ultrathin Pd(100) films. (b) Distribution of thickness. (c) Distribution of lattice constant of ultrathin Pd(100) films with mean thickness of 3.3 nm.


Contacts
Shunsuke Sakuragi
The Institute for Solid State Physics, The Universty of Tokyo
　TEL: +81-4-7136-3477 (over sea)
　E-mail: sakuragiatissp.u-tokyo.ac.jp

SPring-8/SACLA
Information and Outreach Section,
User Administration Division,
Japan Synchrotron Radiation Research Institute (JASRI)
　Email：kouhou@spring8.or.jp
　Tel. +81-791-58-2785, Fax.+81-791-58-2786
Previous Article
Understanding the origin of heat conduction in thin films -Breakthrough for evaluation of thermal properties of energy- efficient devices (Press Release)
Current article
Mechanism of spontaneous lattice distortion to stabilize ferromagnetic state in metals -Clarification of the mechanism behind magnetism appearing in ultrathin metal films expected-(Press Release)