The study of negative thermal expansion and magnetic evolution in antiperovskite compounds Cu0.8-xSnxMn0.2NMn3(0 ≤ x ≤ 0.3)

Abstract

With increasing the substitution of Sn for Cu in Cu 0.8-x Sn x Mn 0.2 NMn 3 , the initial cubic-tetragonal structural phase transition disappears for the samples x ! 0.10 and is replaced by a discontinuous lattice expansion with a cubic structure which has been confirmed by the measurements of variable temperature x-ray diffractions and specific heat. The discontinuous lattice expansion broadens with increasing the doping level x and the negative thermal expansion coefficient up to À64.54 ppm=K between 190 K and 235 K is found for the sample x ¼ 0.3. Detailed magnetic measurements indicate that the magnetic ground state is meta-stable for the lower-doping level and transforms into spin-glass-like state owing to the enhancement of antiferromagnetic interaction when x is up to 0.3. Furthermore, the magnetization curves M(T) display abnormal behaviors for lower-x. For the samples x ¼ 0.1 and 0.2, the jump of field-cooled magnetization curve M FC (defined as DM FC =M FC ) around the lower-temperature magnetic transition is suppressed with increasing the magnetic field. These abnormalities of magnetizations are also discussed based on a simple model.

Enhanced Negative Thermal Expansion in La1–xPrxFe10.7Co0.8Si1.5 Compounds by Doping the Magnetic Rare-Earth Element Praseodymium

“…In recent years, many studies have been conducted on the NTE materials because of their potential applications for high precision devices, such as optical mirrors, fiber-optic systems, and electrooptical sensors, in which it is necessary to compensate for the normal positive thermal expansion. Up to now, several kinds of materials with NTE properties were discovered, such as LiAlSiO 4 (β-eucryptite), ZrW 2 O 8 , , ReO 3 , CuO nanoparticles, ScF 3 , , PbTio 3 -based compounds, La(Fe,Si) 13 -based compounds, and antiperovskite manganese nitride. − It is noteworthy, however, that only a very limited number of NTE materials serve as thermal volume-expansion compensators in practical applications because of the relatively narrow NTE operation-temperature window, low NTE coefficient, thermal expansion anisotropy, and low mechanical strength and electrical conductivity . Among these NTE materials, La(Fe,Si) 13 -based compounds have been recently developed as promising NTE materials, which show large, isotropic, and nonhysteretic NTE properties and relatively high electrical and thermal conductivities.…”

Broad Negative Thermal Expansion Operation-Temperature Window Achieved by Adjusting Fe–Fe Magnetic Exchange Coupling in La(Fe,Si)13 Compounds

“…For instance, the NTE operation-temperature window of the LaFe 9.9 Si 3.1 and LaFe 10.0 Si 3.0 are extended to 190 and 210 K, respectively. For LaFe 10.1 Si 2.9 , the NTE operation-temperature window reaches a considerably wide temperature range of 220 K, which is almost twice larger than that of the typical MVE-driving NTE materials, such as La­(Fe, Si, Co) 13 compounds and doped antiperovskite manganese nitrides. − Besides, the average CTE is −3.9 × 10 –6 K –1 between 225 and 5 K (Δ T = 220 K) for LaFe 10.1 Si 2.9 . More interestingly, the Δ L / L curves show an almost linear increase with decrease in temperature for LaFe 10.0 Si 3.0 and LaFe 9.9 Si 3.1 , which suggests the homogeneity of the coefficient of thermal expansion (CTE) in the NTE operation-temperature window.…”

“…Examples of the most studied NTE materials include several classes such as LiAlSiO 4 (β-eucryptite), ZrW 2 O 8 , , ReO 3 , CuO nanoparticles, materials family of ScF 3 , − PbTiO 3 -based compounds, La­(Fe,Si) 13 -based compounds and doped antiperovskite manganese nitride. − Among these NTE materials, the cubic La­(Fe,Si) 13 -based compounds are recently developed as promising NTE materials, which show large, isotropic and nonhysteretic NTE properties as well as relatively high electrical and thermal conductivity. It is noteworthy, however, that NTE occurs in only a narrow temperature range, generally less than 110 K as reported in earlier paper .…”

Zero Thermal Expansion Polyarylamide Film with Reversible Conformational Change Structure

“…Through years of intensive research, a number of methods have been developed to suppress the positive CTE values of polymers, one of which is to add inorganic fillers with low CTE or negative CTE, such as ZrW 2 O 8 (CTE l = −9 ppm/K, 0–1050 K), ScF 3 (CTE l = −14.0 ppm/K, 60–100 K), and PbTiO 3 (CTE v = −19.9 ppm/K, 298–763 K), and the antiperovskite manganese nitrides family. − These materials could be employed as compensators to reduce the comprehensive CTE values of the resin matrix composites. − However, the lack of interaction between polymer matrix and inorganic fillers limits the effectiveness of this approach. , To avoid these issues, the most straightforward way is to directly incorporate thermal contractile units into polymer chains. Very recently, we have reported that polyarylamides incorporated with s-dibenzocyclooctadiene (DBCOD) exhibited negative thermal expansion (NTE). − The unique contraction mainly originated from the reversible conformational change of DBCODs in the polymer chains.…”