Accession Number:

AD0769030

Title:

Magnetoresistance of a Dilute Ferromagnetic PdMn Alloy: Acoustic- and Optic-Mode Excitations,

Descriptive Note:

Corporate Author:

SUSSEX UNIV BRIGHTON (ENGLAND) SCHOOL OF MATHEMATICAL AND PHYSICAL SCIENCES

Personal Author(s):

• Williams,Gwyn
• Swallow,G. A.
• Loram,J. W.

Report Date:

1972-06-29

Pagination or Media Count:

13.0

Abstract:

Magnetoresistance measurements on a Pd-2.91-at. Mn alloy in the temperature range 1.4-20K and in applied fields up to 60 kOe are presented. The data demonstrate the effects of interimpurity near-neighbor covalent admixture, the antiferromagnetic coupling from which appears to be in qualitative agreement with the calculations of Moriya. These data also allow an estimate of the near-neighbor Mn-Mn interaction energy to be made, and this is compared with quantitative estimates on the basis of the double-resonance coupling mechanism of Caroli and Blandin. By including a magnetic field in the collective-excitation model of Long and Turner, the magnetoresistance data can be fitted once allowance has been made for near-neighbor antiferromagnetic coupling. The acoustic-spin-wave stiffness D, which is obtained by fitting the data to this model, is found to be field dependent it decreases rapidly with increasing field. The possibility of optical-mode collective excitations is briefly discussed. Author

Descriptors:

• *PALLADIUM ALLOYS
• MAGNETIC PROPERTIES
• CRYOGENICS
• MANGANESE ALLOYS
• ELECTRICAL RESISTANCE
• IMPURITIES
• POLARIZATION
• BAND THEORY OF SOLIDS
• ANTIFERROMAGNETISM
• UNITED KINGDOM

Subject Categories:

• Solid State Physics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE