Inverse barocaloric effect in the giant magnetocaloric La–Fe–Si–Co compound

Abstract

Application of hydrostatic pressure under adiabatic conditions causes a change in temperature in any substance. This effect is known as the barocaloric effect and the vast majority of materials heat up when adiabatically squeezed, and they cool down when pressure is released (conventional barocaloric effect). There are, however, materials exhibiting an inverse barocaloric effect: they cool when pressure is applied, and they warm when it is released. Materials exhibiting the inverse barocaloric effect are rather uncommon. Here we report an inverse barocaloric effect in the intermetallic compound La-Fe-Co-Si, which is one of the most promising candidates for magnetic refrigeration through its giant magnetocaloric effect. We have found that application of a pressure of only 1 kbar causes a temperature change of about 1.5 K. This value is larger than the magnetocaloric effect in this compound for magnetic fi elds that are available with permanent magnets.

Multicaloric effect in ferroelectric PbTiO3from first principles

“…Contrary to the old belief that such effects, while common, are miniscule, a large variety of giant caloric effects has been recently discovered in some ferroic materials [1][2][3][4][5][6][7][8][9][10] . These discoveries have opened the door to the use of these giant effects in an efficient and environmentally friendly solid-state refrigeration technology.…”

“…However, except for the Refs. 7,8,10,16, the giant caloric effects were found in very "dissimilar" materials, that are unlikely to "pair" to produce a multiple, or multi-, caloric effect. An alternative strategy in the search for multicaloric materials could be to look for large caloric effects in those ferroics which intrinsically combine more than one ferroic property.…”

“…As a result, it was long believed that the effect is miniscule by its very nature 15 and very little effort was directed towards its understanding, or a search of materials with large caloric effects. There has been a drastic change in the situation, however, in the recent years, thanks to the discoveries of giant magnetocaloric effect 1,2,9 , giant electectrocaloric effect 3,4,6,10 , followed by the reports of giant elastocaloric and barocaloric effects 5,7,8,16 . However, except for the Refs.…”

“…The wide class of ferroics includes such diverse materials as ferromagnets and magnetic materials, ferroelectrics, ferroelastics and multiferroics. As a result, a variety of giant caloric effects has been reported recently with the most notable ones being the giant magnetocaloric 1,2,9 , electrocaloric 3,4,6,10 , barocaloric 7,8 and elastocaloric 5 effects. In addition, the decrease in size of the high quality samples brings the opportunity to further enhance caloric effects through an application of larger fields.…”

“…Moreover, given a relative abundance of extrinsic multiferroics among ferroics with multiple order parameters, such prediction may open an unusual route to solid state refrigeration advancement. Recent discoveries of giant caloric effects in some ferroic materials [1][2][3][4][5][6][7][8][9][10] have opened the door to the use of solidstate materials as an alternative to gases for conventional and cryogenic refrigeration 11 . The wide class of ferroics includes such diverse materials as ferromagnets and magnetic materials, ferroelectrics, ferroelastics and multiferroics.…”