Thermal observables in coupled Cr7Ni molecular rings: Role and quantification of spin-entanglement

Abstract

This work examines the interplay between the thermal observables and the entanglement of molecular magnets conformed by antiferromagnetic rings of Cr7Ni. We show how in the quantification of the spin-entanglement, quantities such as the specific heat C Mag and magnetocaloric observables (MCO) provide further insight into the description of the entanglement between molecular rings. Such quantities reproduce the entanglement-map behavior as a function of the external magnetic field and temperature. Studying ring entanglement in 2(Cr7Ni)L-like molecules (L being a molecular link) is essential in order to understand how to enhance MCO in such heterometallic systems. The magnetic field value at which the system passes from finite entanglement behavior to a factorizable thermal density matrix state is shifted by smooth modifications of the effective exchange couplings, and it is reflected onto C Mag and MCO by shiftable, sharp decrements of such quantities. © 2011 American Institute of Physics.