Evidence for split bands from electronic specific heat and electrical transport data in Fe--V and in other iron and nickel alloys

Conference · Thu Jan 01 00:00:00 EST 1976 · AIP (Am. Inst. Phys.) Conf. Proc.; (United States)

OSTI ID:7125149

Berger, L

In concentrated alloys where the nuclear charges or exchange fields of the components differ sufficiently, the coherent potential approximation predicts that each alloy component has its own 3d band, having minimal overlap with the 3d bands of other components. This ''split-band model'' applies well to the spin-down bands of fcc Ni--Fe, Ni--Fe--Cu, etc., and explains many of their properties. For example, several physical quantities exhibit anomalies when the Fermi level epsilon/sub F/ crosses the boundary T between nickel and iron bands. A systematic search for bcc iron-base alloy series where the spin-up band might be split, and where epsilon/sub F/ might cross a boundary T between bands, yields Fe--V. As expected, the electronic specific heat coefficient ..gamma.. of Fe--V has a minimum when epsilon/sub F/ is at T, around 15 at. percent V. The electrical resistivity rho, the slope rho/sup -1/ d rho/dH, and the anomalous Hall coefficient R/sub s/ have sharp anomalies close by. The magnetoresistance ..delta.. rho/rho/sub 0/ is unusually large in FeV. A scattering resonance in the solvent band close to T leads to large ..cap alpha.. = rho/sub up arrow//rho/sub down arrow/, hence to these large ..delta..rho/rho/sub 0/. The observed decrease of ..delta..rho/rho/sub 0/ when epsilon/sub F/ crosses T into the vanadium band reflects a decrease of value of the matrix elements of spin-orbit interaction. Similar series such as Fe--Cr, Fe--Mo, Fe--W, Fe--Ti, Fe--Nb, are also discussed.

• Research Organization: Carnegie-Mellon Univ., Pittsburgh
• OSTI ID: 7125149
• Journal Information: AIP (Am. Inst. Phys.) Conf. Proc.; (United States), Vol. 34; Conference: Joint international magnetism and magnetic materials intermag conference, Pittsburgh, PA, USA, 15 Jun 1976; Other Information: See CONF-760619--
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
IRON ALLOYS
ELECTRONIC STRUCTURE
VANADIUM ALLOYS
CHROMIUM ALLOYS
MOLYBDENUM ALLOYS
TITANIUM ALLOYS
NIOBIUM ALLOYS
BAND THEORY
BCC LATTICES
ELECTRIC CONDUCTIVITY
ELECTRONIC SPECIFIC HEAT
FERMI LEVEL
ALLOYS
CRYSTAL LATTICES
CRYSTAL STRUCTURE
CUBIC LATTICES
ELECTRICAL PROPERTIES
ENERGY LEVELS
PHYSICAL PROPERTIES
SPECIFIC HEAT
THERMODYNAMIC PROPERTIES
360104* - Metals & Alloys- Physical Properties