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Competing localization and quantum interference effects in Fe 0.9 Co 0.1 Si
Author(s) -
Samatham S. Shanmukharao,
Venkateshwarlu D.,
Gangrade Mohan,
Ganesan V.
Publication year - 2012
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/pssb.201248237
Subject(s) - magnetoresistance , condensed matter physics , ferromagnetism , paramagnetism , electrical resistivity and conductivity , magnetic field , weak localization , quantum interference , electron localization function , electron , materials science , physics , chemistry , superconductivity , quantum mechanics
Unusual magnetoresistance observed in weak itinerant ferromagnetic metal Fe 0.9 Co 0.1 Si is addressed. We invoke localization effects significantly contributing to the positive magnetoresistance apart from quantum interference effects (QIE), a new mechanism for magnetoresistance at low temperatures. QIE are dominant only at very low temperatures while localization effects are progressive out of the sub‐Kelvin domain. Dominance of localization effects in Kelvin range with increasing applied magnetic field is demonstrated. An unconventional effect of magnetic field on resistivity, favors a least dominant role of ferromagnetic correlations. The H – T phase diagram explore the regions of H 3/2 (paramagnetic region) and QIE (Δ σ ∝ H 1/2 ) and its extension into the paramagnetic region. A new region of linear field dependence of MC (Δ σ ∝ H ) is also found and reported. Qualitative analysis of thermopower and its correspondence with electrical resistivity strengthens the concept that the same electrons are responsible for both electrical and magnetic properties. It is also reported that the onset of magnetic and QIE effects is well above T C .