Domain hyperfine fields in some dilute ferromagnetic alloys studied by NMR on oriented nuclei. [Fe alloys with Co and Ni additions]

Technical Report · Sat May 01 00:00:00 EDT 1976

OSTI ID:7359242

Streater, R W

Hyperfine field distributions at the sites of /sup 60/Co atoms dissolved in some dilute (up to 4 percent) CoFe and NiFe alloys were measured by NMR on oriented nuclei at very low temperatures. The hyperfine field shifts due to neighboring impurities are shown to be consistent with a model in which the shifts are caused by moment perturbations in the neighboring shells surrounding an impurity, with RKKY-like spin density oscillations affecting the conduction electron and core polarization contributions to the hyperfine field. The observed shifts at a /sup 60/Co site are +1.86 +- 0.22 kG with a nearest neighbor substituent Co, -4.28 +- 0.17 kG with a second nearest neighbor substituent, -3.41 +- 0.07 kG for a third nearest neighbor substituent and -0.98 +- 0.05 kG for a fourth nearest neighbor substituent. In the NiFe alloys, the shifts are -3.48 +- 0.23 kG, -6.63 +- 0.14 kg, -5.14 +- 0.25 kG, and -1.49 +- 0.14 kG respectively for Ni neighbors. The shifts are shown to be generally smaller than those at the Fe sites, the trends being consistent with a reduced number of itinerant electrons in going across the 3d transition series and with the moment perturbations arising via the itinerant d's. Small quadrupole contributions to the hyperfine interactions are shown to exist by the response in adiabatic fast passage resonance sweeps, but do not contribute significantly to the magnetic resonance lineshapes. /sup 60/Co spin-lattice relaxation times were measured for the main and satellite resonances in some CoFe alloys and no statistically significant changes in a function of alloy concentration or the sub-resonance excited were observed.

• Research Organization: California Univ., Berkeley (USA). Lawrence Berkeley Lab.
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 7359242
• Report Number(s): LBL-4981
• Resource Relation: Other Information: Thesis
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
COBALT 60
NUCLEAR MAGNETIC RESONANCE
IRON BASE ALLOYS
HYPERFINE STRUCTURE
COBALT ADDITIONS
DILUTE ALLOYS
DOMAIN STRUCTURE
FERROMAGNETIC MATERIALS
MAGNETIC FIELDS
NICKEL ADDITIONS
ORIENTED NUCLEI
SPIN-LATTICE RELAXATION
ALLOYS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
COBALT ALLOYS
COBALT ISOTOPES
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
IRON ALLOYS
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
MAGNETIC MATERIALS
MAGNETIC RESONANCE
MATERIALS
MINUTES LIVING RADIOISOTOPES
NICKEL ALLOYS
NUCLEI
ODD-ODD NUCLEI
RADIOISOTOPES
RELAXATION
RESONANCE
YEARS LIVING RADIOISOTOPES
360104* - Metals & Alloys- Physical Properties