Premium
Domain structures in single crystal magnetite below the Verwey Transition as observed with a low‐temperature magnetic force microscope
Author(s) -
Moloni Katerina,
Moskowitz Bruce M.,
Dahlberg E. Dan
Publication year - 1996
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/96gl00962
Subject(s) - magnetite , magnetocrystalline anisotropy , condensed matter physics , materials science , magnetic domain , crystal twinning , magnetic force microscope , charge ordering , domain wall (magnetism) , crystal (programming language) , anisotropy , domain (mathematical analysis) , single domain , magnetic anisotropy , crystallography , charge (physics) , magnetic field , optics , magnetization , physics , chemistry , composite material , microstructure , metallurgy , mathematical analysis , programming language , mathematics , quantum mechanics , computer science
The magnetic domain structures on the {110} plane of magnetite (Fe 3 O 4 ) below the Verwey transition (T v =120K) were studied using a Low‐Temperature Magnetic Force Microscope (LTMFM). At 298K, domain structures consisted of arrays of 180°, 109° and 71° walls, typical for magnetite with cubic anisotropy. At 77K (below T v ), the cubic style patterns disappeared and transformed into uniaxial patterns consistent with the uniaxial magnetocrystalline symmetry of the low‐temperature monoclinic phase of magnetite. We also observed two distinct styles of domain patterns below T v : (1) wide domains separated by straight 180° walls along the in‐plane [100] easy axis; and (2) intricate wavy walls with reverse spike domains characteristic of out‐of‐plane easy axes. This intimate mixture of domain styles within adjacent areas of the crystal reflects variations in the direction of the magnetic easy axes in different regions produced by c‐axis twinning of the crystal below T v The thermal dependence of planar and wavy‐wall patterns show little change from 77K until 110K, where patterns disappear. Upon cooling back to 77K, domain structures are different from the initial 77K states, indicating that renucleation of different domain states occurs by cycling near T v .