M. S. Reis

Experimental determination of thermal entanglement in spin clusters using magnetic susceptibility measurements

The present work reports an experimental observation of thermal entanglement in a clusterized spin chain formed in the compound

Entanglement and Bell's inequality violation above room temperature in metal carboxylates.

{\mathrm{Na}}_{2}{\mathrm{Cu}}_{5}{\mathrm{Si}}_{4}{\mathrm{O}}_{14}

The giant anisotropic magnetocaloric effect in DyAl2

. The presence of entanglement was investigated through two measured quantities, an entanglement witness and the entanglement of formation, both derived from the magnetic susceptibility. It was found that pairwise entanglement exists below

Magnetic behavior of a nonextensive S -spin system: Possible connections to manganites

\ensuremath{\sim}200\phantom{\rule{0.3em}{0ex}}\mathrm{K}

Evidences for Tsallis non-extensivity on CMR manganites

. Tripartite entanglement was also observed below

Entanglement temperature in molecular magnets composed of S-spin dimers

\ensuremath{\sim}240\phantom{\rule{0.3em}{0ex}}\mathrm{K}

Polymer encapsulation effects on the magnetism of EuS nanocrystals

. A theoretical study of entanglement evolution as a function of applied field and temperature is also presented.

High refrigerant capacity of PrNi5−xCox magnetic compounds exploiting its spin reorientation and magnetic transition over a wide temperature zone

In the present work we show that a particular family of materials, the metal carboxylates, may have entangled states up to very high temperatures. From magnetic-susceptibility measurements, we have estimated the critical temperature below which entanglement exists in the copper carboxylate {Cu-2(O2CH)(4)}{Cu(O2CH)(2)(2-methylpyridine)(2)}, and we have found this to be above room temperature (T-e similar to 630 K). Furthermore, the results show that the system remains maximally entangled until close to similar to 100 K and the Bells inequality is violated up to nearly room temperature (similar to 290 K).

Evidence for entanglement at high temperatures in an engineered molecular magnet

We report on calculations of the anisotropic magnetocaloric effect in DyAl2 using a model Hamiltonian including crystalline electrical field effects. The anisotropic effect is produced by the rotation of a constant magnetic field from the easy to a hard magnetic direction in the crystal and is enhanced by the first order nature of the field induced spin reorientation transition. The calculated results indicate that for a field with modulus of 2 T rotating from a hard to the easy direction, the isothermal magnetic entropy (ΔSiso) and adiabatic temperature (ΔTad) changes present peak values higher than 60% the ones observed in the usual process, in which the field direction is kept constant and the modulus of the field is varied.

A comparative study of the magnetocaloric effect in RNi2 (R=Nd,Gd,Tb) intermetallic compounds

We analyzed the magnetic behavior of a S-spin system within the framework of Tsallis nonextensive statistics, employing the normalized approach. Unusual properties on magnetization, entropy, and susceptibility emerge as a consequence of the nonextensivity. We further show that the nonextensive approach can be relevant to the field of manganites, materials which exhibit long-range interactions and fractality, two basic ingredients for nonextensivity. Our results are in qualitative agreement with experimental data in