Magnetic viscosity studies in hard magnetic materials

Journal Article · Tue May 01 00:00:00 EDT 1990 · Journal of Applied Physics; (USA)

DOI:https://doi.org/10.1063/1.344777· OSTI ID:6838251

Singleton, E W; Hadjipanayis, G C ^[1]

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1. Department of Physics, Cardwell Hall, Kansas State University, Manhattan, Kansas 66506 (USA)

The magnetic viscosity behavior has been studied in several hard magnets with different magnetization reversal mechanisms including barium ferrite powders, Cu-Mn-Al, ferrite magnets, Nd-Fe-B, and SmCo{sub 5}, Sm{sub 2}(Co,Fe,Cu,Zr){sub 17}. The measurements were made with a vibrating sample magnetometer for times up to 60 s and a SQUID magnetometer for longer times in the range of 60--2300 s. For most of the samples the magnetization was found to vary logarithmically with time. The field and temperature dependence of the magnetic viscosity coefficient {ital S} was studied. Here, {ital S} was found to vary with the applied field and it usually peaked around the coercive field {ital H}{sub {ital c}}. The measured values of {ital S}{sub max} at 10 K range from 0.004 to 1.853 emu/g for Cu-Mn-Al and Sm{sub 2}(Co,Fe,Cu,Zr){sub 17}, respectively. The magnetic viscosity coefficient was used together with the magnetic susceptibility to determine the activation volume.

• OSTI ID: 6838251
• Journal Information: Journal of Applied Physics; (USA), Vol. 67:9; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
MAGNETIC PROPERTIES
BORON ALLOYS
COPPER ALLOYS
IRON ALLOYS
MANGANESE ALLOYS
NEODYMIUM ALLOYS
SAMARIUM ALLOYS
ZIRCONIUM ALLOYS
MAGNETIC FIELDS
MAGNETOMETERS
TEMPERATURE MEASUREMENT
VISCOSITY
ALLOYS
MEASURING INSTRUMENTS
PHYSICAL PROPERTIES
RARE EARTH ALLOYS
360104* - Metals & Alloys- Physical Properties