Giant negative thermal expansion at the nanoscale in the multifunctional material Gd-5(Si, Ge)(4)

• Type: Article in International Scientific Journal
• Date: 2019

Authors

Belo, JH (Author) FCUP; Pires, AL (Author) Other; Gomes, IT (Author) Other; Andrade, V (Author) Other; Sousa, JB (Author) Other; Hadimani, RL (Author) Other; Jiles, DC (Author) Other; Ren, Y (Author) Other; Zhang, XY (Author) Other; araujo, j. p. (Author) FCUP; pereira, a. m. (Author) FCUP

Journal

Title: Physical Review B

Vol. 100

ISSN: 2469-9950

Publisher: American Physical Society

Indexing

ISI Web of Knowledge - 22 Citations

Scopus - 25 Citations

Other information

Authenticus ID: P-00R-4SK

DOI: 10.1103/physrevb.100.134303

Abstract (EN): In this work the thermal expansion of Gd5Si1.3Ge2.7 magnetic nanogranules was studied. A crossover from positive (macro- and microscale in the literature) towards a negative thermal expansion (at nanoscale) is observed. The negative thermal expansion (NTE) behavior was found in two temperature windows: 90-160 K (beta(LT) similar to-32.2 ppm K-1), and within the room temperature 255-340 K, where a giant NTE was observed (-69 ppm K-1). The key atomic mechanism driving the NTE is identified as an atomic triplet-chain flexibility. The results suggest that the NTE behavior emerges as a size-reduction effect caused by the intrinsic nanoparticles surface pressure (estimated at 11 kbar), leading to the positive thermal expansion-NTE crossover at the nanoscale.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 7