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Irradiation‐Induced Electron Tunnelling and Small‐Polaron Hopping in Single‐Crystalline YIG
Author(s) -
Walz F.,
Brabers J.H.V.J.,
Torres L.,
Kronmüller H.
Publication year - 2001
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/1521-3951(200112)228:3<717::aid-pssb717>3.0.co;2-8
Subject(s) - polaron , condensed matter physics , quantum tunnelling , yttrium iron garnet , charge ordering , ferrimagnetism , ionic bonding , materials science , selenide , electron , ion , chemistry , physics , charge (physics) , magnetization , magnetic field , selenium , organic chemistry , quantum mechanics , metallurgy
In electron (e — )‐irradiated (>10 23 e — m —2 ) single crystalline yttrium‐ion Garnet (YIG), after moderate annealing, low‐temperature ( T < 125 K) magnetic after‐effect (MAE) spectra are observed which are of striking similarity to the well investigated spectra occurring in magnetite (Fe 3 O 4 ) below the Verwey transition ( T V ≈ 125 K). Our analysis shows that this similarity is the result of corresponding relaxation mechanisms in both systems, i.e. electron tunnelling and small‐polaron hopping. Deeper insights into these mechanisms are obtained from a thorough inspection of these spectra and their physical preconditions in the two, a‐priori, completely different ferrimagnetic systems: (i) semiconductor , transformed into a quasi‐insulating state due to long‐range ionic ordering at low‐temperatures (Fe 3 O 4 ) and (ii) insulator , brought into a state of low resistivity due to radiation‐induced perturbations of the charge equilibrium (YIG).