Negative thermal expansion induced by intermetallic charge transfer

Negative thermal expansion induced by intermetallic charge transfer

Suppression of thermal expansion is of great importance for industry. Negative thermal expansion (NTE) materials which shrink on heating and expand on cooling are therefore attracting keen attention. Here we provide a brief overview of NTE induced by intermetallic charge transfer in A-site ordered double perovskites SaCu3Fe4O12 and LaCu3Fe4-x Mn x O12, as well as in Bi or Ni substituted BiNiO3....

Colossal negative thermal expansion in BiNiO3 induced by intermetallic charge transfer

The unusual property of negative thermal expansion is of fundamental interest and may be used to fabricate composites with zero or other controlled thermal expansion values. Here we report that colossal negative thermal expansion (defined as linear expansion <-10(-4) K(-1) over a temperature range ~100 K) is accessible in perovskite oxides showing charge-transfer transitions. BiNiO(3) shows a 2...

Negative Thermal Expansion

Introduction Many materials which we encounter in everyday life expand on heating. This fact of life is easily highlighted with a simple experiment that we are all familiar with and involves a metallic sphere passing through a metal ring. At room temperature, the sphere is of such a size that it can easily pass through the ring, but after the sphere is heated, it will have expanded with the res...

Thermal Expansion of Several Sn-based Intermetallic Compounds

Negative Thermal Expansion in Ba0.5Sr0.5Zn2SiGeO7

Solid solutions with the composition Ba0.5Sr0.5Zn₂Si2-xGexO₇ and BaZn₂Si2-xGexO₇ were prepared with different values of x using a conventional mixed oxide route. Both compounds exhibit very different thermal expansion, which is due to the different crystal structures. Ba0.5Sr0.5Zn₂Si2-xGexO₇ solid solutions exhibit the structure of high-temperature BaZn₂Si₂O₇ and show negative thermal expansion...