Influence of Mn moments on the properties of RMn sub 2 compounds (R=Y and light rare earths)

Journal Article · Tue May 01 04:00:00 EDT 1990 · Journal of Applied Physics; (USA)

DOI:https://doi.org/10.1063/1.344614· OSTI ID:6838187

Labroo, S; Willis, F; Ali, N ^[1]

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1. Department of Physics, Southern Illinois University, Carbondale, IL (USA) Molecular Science Program, Southern Illinois University, Carbondale, Illinois 62901 (USA)

The influence of Mn moments on the magnetism of RMn{sub 2} compounds, where R=Y, Pr, Nd, and Sm, has been investigated using SQUID magnetometry, thermal expansion, electrical resistivity, and magnetoresistance measurements. RMn{sub 2} compounds, with R=Y, Pr, Nd, and Sm, order antiferromagnetically at 116, 115, 105, and 94 K, respectively. According to thermal expansion data all these materials undergo a first-order phase transition from a paramagnetic to a magnetically ordered state, and this effect is believed to be caused by the collapse of the Mn moment at the transition. For the YMn{sub 2} compound, the resistivity has a {ital T}{sup 3} temperature dependence below 38 K and a positive magnetoresistance in the ordered phase, indicating that the Mn moments are localized below {ital T}{sub {ital N}} in this compound. Above {ital T}{sub {ital N}}, however, the Mn moments become itinerant which is reflected as a gradual increase in susceptibility {chi} with increasing temperature. In PrMn{sub 2}, NdMn{sub 2}, and SmMn{sub 2} the resistivity does not follow a simple temperature power law and the magnetoresistance varies from negative to positive values depending on the temperature and field. The transition temperatures in these materials differ significantly from the de Gennes factor and it is believed that the ordering is brought about by antiferromagnetic coupling between Mn moments.

• OSTI ID: 6838187
• Journal Information: Journal of Applied Physics; (USA), Journal Name: Journal of Applied Physics; (USA) Vol. 67:9; ISSN 0021-8979; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
ALLOYS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELECTRONIC EQUIPMENT
EQUIPMENT
EXPANSION
FLUXMETERS
LOW TEMPERATURE
MAGNETIC MOMENTS
MAGNETIC PROPERTIES
MAGNETIC SUSCEPTIBILITY
MAGNETORESISTANCE
MANGANESE ALLOYS
MEASURING INSTRUMENTS
MEDIUM TEMPERATURE
MICROWAVE EQUIPMENT
PHYSICAL PROPERTIES
RARE EARTH ALLOYS
SQUID DEVICES
SUPERCONDUCTING DEVICES
THERMAL EXPANSION
ULTRALOW TEMPERATURE
VERY LOW TEMPERATURE