scholarly journals Magnetism of F centers; Indication of an antiferromagnetic phase transition in potassium-electro-sodalite

2000 ◽  
Vol 65 (5-6) ◽  
pp. 311-314 ◽  
Author(s):  
Ljiljana Damjanovic ◽  
Galen Stucky ◽  
Vojislav Srdanov
Keyword(s):  
Phase Transition ◽  
Exchange Interaction ◽  
Contact Interaction ◽  
Unpaired Electron ◽  
Potassium Atom ◽  
Antiferromagnetic Phase ◽  
Temperature Dependent ◽  
Fermi Contact Interaction ◽  
Fermi Contact ◽  
Lower Temperature

Temperature-dependent EPR data of potassium-electro-sodalite (PES), K8[Al6Si6O24](e-)2, are consistent with the occurrence of an antiferromagnetic phase transition at 71?2 K. PES is a Mott insulator which contains an unpaired electron in every sodalite cage. The same transition in sodium-electro-sodalite occurs at a considerably lower temperature (42 K), indicating that the exchange interaction among localized electrons is stronger in PES. PES is obtained by the inclusion of one potassium atom in every cage of potassium sodalite. The 27 Al MAS NMR resonance of PES is shifted downfield in respect to diamagnetic potassium-sodalite, K6[Al6Si6O24]. The NMR shift is due to unpaired electrons and is caused by hyperfine Fermi contact interaction.

The hydrogen atom in the presence of the Fermi-contact interaction

1970 ◽  
Vol 18 (5) ◽  
pp. 693-696 ◽  
Author(s):  
A. Velenik ◽  
T. Živković ◽  
W.H. de Jeu ◽  
J.N. Murrell
Keyword(s):  
Hydrogen Atom ◽  
Contact Interaction ◽  
Fermi Contact Interaction ◽  
Fermi Contact

The equiatomic intermetallics REPtCd (RE= La, Ce, Pr, Nd, Eu) and magnetic properties of CeAuCd

2015 ◽  
Vol 70 (3) ◽  
pp. 197-202 ◽  
Author(s):  
Michael Johnscher ◽  
Frank Tappe ◽  
Oliver Niehaus ◽  
Rainer Pöttgen
Keyword(s):  
Phase Transition ◽  
Three Dimensional ◽  
Induction Melting ◽  
Antiferromagnetic Phase ◽  
Crystal Data ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
Magnetic Susceptibility Data ◽  
X Ray ◽  
Susceptibility Data

AbstractThe cadmium intermetallics REPtCd (RE = La, Ce, Pr, Nd, Eu) and CeAuCd were synthesized by induction-melting of the elements in sealed niobium ampoules followed by annealing in muffle furnaces. The samples were characterized by powder X-ray diffraction. The structures of CePtCd (ZrNiAl type, $P\bar 62m,$a = 763.8(6), c = 409.1(4) pm, wR2 = 0.0195, 298 F2 values, 14 variables) and EuPtCd (TiNiSi type, Pnma, a = 741.3(2), b = 436.4(1), c = 858.0(4) pm, wR2 = 0.0385, 440 F2 values, 20 variables) were refined from single-crystal data. The REPtCd structures exhibit three-dimensional networks of corner- and edge-sharing Cd@Pt2/6Pt2/3 and Cd@Pt4/4 tetrahedra, which leave cages for the rare earth atoms. Temperature-dependent magnetic susceptibility data of CeAuCd reveal a paramagnetic to antiferromagnetic phase transition at TN = 3.7(5) K.

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