Transverse and longitudinal spin-fluctuations in INVAR Fe0.65Ni0.35

Journal article

The presence of spin-fluctuations deep within the ordered state of ferromagnetic [Formula: see text] alloy [Formula: see text] has long been suspected but seldom directly observed. Inhomogeneities of one type or another have been cited as important in stabilizing [Formula: see text] behaviour-either longitudinal spin-fluctuations associated with the [Formula: see text]-state (local environment) model or transverse magnetisation arising from non-collinear spin structures. In this study we employ small-angle neutron scattering with neutron polarization analysis to distinguish between the two possibilities. Surprisingly we in fact find evidence of dominant but uncorrelated longitudinal spin-fluctuations coexisting with transverse magnetisation which exists in short-range clusters of size ~[Formula: see text]. This finding supports recent first principles calculations of [Formula: see text] in which both longitudinal spin-fluctuations and magnetic short-range order are identified as important ingredients in reproducing the equilibrium [Formula: see text] lattice.

Authors: Stewart, JR; Giblin, SR; Honecker, D; Fouquet, P; Prabhakaran, D

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: IOP Publishing
• Journal: Journal of Physics: Condensed Matter
• Volume: 31
• Issue: 2
• Article number: 025802
• Publication date: 2018-12-06
• Acceptance date: 2018-11-06
• DOI: 10.1088/1361-648x/aaeeaf
• EISSN: 1361-648X
• ISSN: 0953-8984
• Pmid: 30521485
• Language: English
• Keywords: INVAR effect; polarized neutron scattering; small angle neutron scattering