Crystal structure and ferromagnetic phase transitions in CeCu1-xGe1+x (0.0.3ex<=xx.3ex<=x 0.3)
Abstract
As revealed in the powder x-ray diffraction and crystallographic data, the single phase sample in the series CeCu1-xGe1+x (0.0.3ex<=x x.3ex<=x 0.3) crystallizes in the AlB2-type structure with space group P6/mmm. The maximum ferromagnetic transition temperature Tc in CeCu1-xGe1+x, as determined from the electrical- resistivity and magnetic susceptibility measurements, is 10.6 K for the compound CeCu0.8Ge1.2. The magnetic susceptibility for each sample in CeCu1-xGe1+x (0.0.3ex<=x x.3ex<=x 0.3) follows Curie's behavior between 100 and 300 K with an effective moment 2.6±0.1 μB/Ce atom, a value close to that of Ce^3+. However, the observed saturation magnetic moment values (0.96 ∼ 1.15 μB) at low temperatures for all these compounds are well less than the theoretically expected value 2.14 μB for the free Ce^3+ ion tangling the entire six-fold J = 5/2 multiplet. Subtracting the estimated phonon contribution from LaCuGe, the entropy associated with the magnetic structure of CeCuGe is found to meet the theoretical value of Rln2, which would be expected for a doublet ground state of Ce^3+ ion in the compound CeCuGe. The reduced saturation moment in CeCu1-xGe1+x is reasonably ascribed to partial lifting of the 4f-electron level degeneracy.
- Publication:
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APS March Meeting Abstracts
- Pub Date:
- February 2012
- Bibcode:
- 2012APS..MAR.S1264L