Accession Number : AD0466667


Title :   THE MAGNETIC AND THERMAL PROPERTIES OF CR3(CH3COO) 6(OH)2 C1.8H20, A SYSTEM OF CLUSTERS OF THREE CR+++ IONS'.


Descriptive Note : Technical rept.,


Corporate Author : CARNEGIE INST OF TECH PITTSBURGH PA DEPT OF PHYSICS


Personal Author(s) : Uryu, Norikiyo ; Friedberg, S A


Report Date : 01 Jul 1965


Pagination or Media Count : 1


Abstract : The paramagnetic susceptibility and magnetic specific heat of the complex salt (Cr3(CH3COO)6 (OH)2)Cl .8H2O are examined theoretically in the light of recently obtained knowledge of its crystal structure. Each unit cell contains four isolated triangular clusters of three Cr(+++) ions. The crystal properties may be calculated from the Hamiltonian of a single cluster. The structural evidence neither confirms nor excludes clearly the long-conjectured possibility that a cluster has less than trigona symmetry. In an attempt to construct possible alternatives to Kambe's theory which requires cluster distortion, the energy levels of a cluster have been calculated assuming equal isotropic exchange interaction. In order to split the two Kramers doublets comprising the ground state as required by experiment and retain the cluster symmetry a higher order spin interaction is required. Fitting the low temperature specific heat and susceptibility one finds J sub zero = 30k and J'=0.9k, with a slightly smaller value of J' required to fit the susceptibility at higher temperatures. The plausibility of such a novel interaction is considered as is the ordered spin arrangement within a cluster at low temperatures.


Descriptors :   *PERMEABILITY(MAGNETIC) , SPECIFIC HEAT , GROUND STATE , SPINNING(MOTION) , FUNCTIONS(MATHEMATICS) , MOMENTUM , MATRICES(MATHEMATICS)


Distribution Statement : APPROVED FOR PUBLIC RELEASE