The generalized Lindemann melting coefficient

Lindemann developed the melting temperature theory over 100 years ago, known as the Lindemann criterion. Its main assumption is that melting occurs when the root-mean-square vibration amplitude of ions and atoms in crystals exceeds a critical fraction, η of the inter-atomic spacing in crystals. The Lindemann coefficient η is undefined and scientific papers report different η values for different elements. Here we present previously unobserved data trends pointing to the fact that the Lindemann coefficient could be linked to the periodic groups of the periodic table, having an exact value for each element belonging to a given periodic group. We report 12 distinctive Lindemann coefficient values corresponding to 12 groups of the periodic table containing solid elements with identifiable melting temperature. Using these vales, the recalculation of the melting temperatures indicates a good match to the experimental values for 39 elements, corresponding to 12 out of 15 periodic groups. This newly observed result opens up the possibility of further refining the Lindemann melting criterion by stimulating analytical studies of the Lindemann coefficient in the light of this newly discovered result

Solid-State Heating Using the Multicaloric Effect in Multiferroics

The multicaloric effect is defined as the adiabatic reversible temperature change in multiferroic materials induced by the application of an external electric or magnetic field, and it was first theoretically proposed in 2012. The multicaloric effects in multiferroics, as well as other similar caloric effects in single ferroics, such as magnetocaloric, elastocaloric, barocaloric, and electrocaloric, have been the focus of much research due to their potential commercialization in solid-state refrigeration. In this short communication article, we examine the thermodynamics of the multicaloric effect for solid-state heating applications. A possible thermodynamic multicaloric heating cycle is proposed and then implemented to estimate the solid-state heating effect for a known electrocaloric system. This work offers a path to implementing caloric and multicaloric effects to efficient heating systems, and we offer a theoretical estimate of the upper limit of the temperature change achievable in a multicaloric cooling or heating effect