Metamagnetism in Neptunium(V) Oxalate
1972; American Institute of Physics; Volume: 56; Issue: 3 Linguagem: Inglês
10.1063/1.1677368
ISSN1520-9032
Autores Tópico(s)Crystal Structures and Properties
ResumoMagnetic properties of neptunium(V) oxalate, (NpO2)2C2O4·4H2O, were studied from 2.4 to 37.5°K with magnetic-susceptibility measurements using a vibrating-sample magnetometer at applied fields of 50–10 000 Oe; Mössbauer spectra of the 59.54−keV γ ray in 237Np were taken from 4.2 to 80°K. A metamagnetic transition was found at 11.6°K. Below 11.6°K the magnetization isotherms had the characteristic S shape of metamagnets. Below 8°K a pronounced hysteresis was observed as the field was reduced from saturation. At 3.15°K the remanent magnetization at 100 Oe was 96% of the saturation magnetization at 10 000 Oe, and 125 times greater than the magnetization in the low-moment state. The Mössbauer spectra exhibited magnetic hyperfine splitting which was independent of temperature, with g0μnHeff = 10 cm/sec; splitting above the transition temperature is attributed to a long paramagnetic relaxation time.
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