Ultrawide temperature range super-invar behavior of R2(Fe,Co)17 materials (R = rare earth)

DOI: 10.1103/PhysRevLett.127.055501

Authors: Yili Cao (University of Science and Technology Beijing) , Kun Lin (Vienna University of Technology) , Sergii Khmelevskyi (Vienna University of Technology) , Maxim Avdeev (ustralian Nuclear Science and Technology Organisation; The University of Sydney) , Keith M. Taddei (Oak Ridge National Laboratory) , Qiang Zhang (Oak Ridge National Laboratory) , Qingzhen Huang (NIST Center for Neutron Research, National Institute of Standards and Technology) , Qiang Li (University of Science and Technology Beijing) , Kenichi Kato (RIKEN SPring- 8 Center) , Chiu Chung Tang (Diamond Light Source) , Alexandra Gibbs (ISIS Neutron and Muon Source) , Chin-Wei Wang (National Synchrotron Radiation Research Center) , Jinxia Deng (University of Science and Technology Beijing) , Jun Chen (University of Science and Technology Beijing) , Hongjie Zhang (Changchun Institute of Applied Chemistry, Chinese Academy of Sciences) , Xianran Xing (University of Science and Technology Beijing)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Physical Review Letters , VOL 127

State: Published (Approved)
Published: July 2021

Abstract: Super Invar (SIV), i.e., zero thermal expansion of metallic materials underpinned by magnetic ordering, is of great practical merit for a wide range of high precision engineering. However, the relatively narrow temperature window of SIV in most materials restricts its potential applications in many critical fields. Here, we demonstrate the controlled design of thermal expansion in a family of R 2 ( Fe , Co ) 17 materials ( R = rare Earth). We find that adjusting the Fe-Co content tunes the thermal expansion behavior and its optimization leads to a record-wide SIV with good cyclic stability from 3–461 K, almost twice the range of currently known SIV. In situ neutron diffraction, Mössbauer spectra and first-principles calculations reveal the 3 d bonding state transition of the Fe-sublattice favors extra lattice stress upon magnetic ordering. On the other hand, Co content induces a dramatic enhancement of the internal molecular field, which can be manipulated to achieve “ultrawide” SIV over broad temperature, composition and magnetic field windows. These findings pave the way for exploiting thermal-expansion-control engineering and related functional materials.

Journal Keywords: Thermal expansion; Ferrimagnets; Polycrystalline materials; Density functional theory; Neutron irradiation

Subject Areas: Materials, Physics

Facility: Advanced Photon Source

Added On: 17/08/2021 10:00

Discipline Tags:

Physics Magnetism Materials Science Metallurgy

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