Large Linear Negative Thermal Expansion in NiAs-type Magnetic Intermetallic Cr–Te–Se Compounds

A large linear negative thermal expansion (NTE) and expanded NTE temperature range (ΔTNTE) were obtained in magnetoelastic CrTe1–xSex(0 ≤ x≤ 0.15) compounds. For CrTe compound, its thermal expansion coefficient of volume (αV) was calculated to be −28.8 ppm K–1with the temperature ranging from 280 to 340 K. Substituting Te with Se atoms, the NTE behavior and magnetic properties can be well manipulated. With increasing Se in CrTe1–xSex(0 ≤ x≤ 0.15) compounds, the ΔTNTEincreases from 60 K (280–340 K for x= 0), to 80 K (240–320 K for x= 0.05), to 95 K (200–295 K for x= 0.1), and finally to 100 K (170–270 K for x= 0.15). Furthermore, a linear NTE remains independent of temperature for samples with x≤ 0.1. The relationship between tunable NTE and magnetic properties was analyzed in detail, indicating that the NTE in CrTe1–xSexcompounds originates from the magnetovolume effect (MVE).