Evolution of two-step magnetic transition on nanogranular Gd5Si1.3Ge2.7 thin film

• Type: Article in International Scientific Journal
• Date: 2020

Authors

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

Journal

Title: Journal of Physics Condensed Matter

Vol. 32

ISSN: 0953-8984

Publisher: Institute of Physics Publishing

Indexing

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Other information

Authenticus ID: P-00R-YX2

DOI: 10.1088/1361-648x/ab79f9

Abstract (EN): A multi-functional Gd5Si1.3Ge2.7 thin film deposited by pulsed laser ablation in the form of an ensemble of nanoparticles was studied for 18 thermal cycles via electron transport measurements together with structural and magnetic characterization. A general negative thermal dependency of the resistivity (rho) is observed, which contrasts with the metallic-like behavior observed in bulk Gd5SixGe4-x compounds. This general trend is interrupted by a two-step, positive-slope transition in rho(T) throughout the [150, 250] K interval, corresponding to two consecutive magnetic transitions: a fully coupled magnetostructural followed by a magnetic order on heating. An avalanche-like behavior is unveiled by the partial differential rho/ partial differential T(T) curves and is explained based on the severe strains induced cyclically by the magnetostructural transition, leading to a cycling evolution of the transition onset temperature ( partial differential Th '' n similar to 1.6 K/cycle, n being the number of cycles). Such behavior is equivalent to the action of a pressure of 0.56 kBar being formed and building up at every thermal cycle due to the large volume induced change across the magnetostructural transition. Moreover the thermal hysteresis, detected in both rho and magnetization versus temperature curves, evolves significantly along the cycles, decreasing as n increases. This picture corroborates the thermal activation energy enhancement-estimated via an exponential fitting of the partial differential rho/ partial differential T(T) in the avalanche regime. This work demonstrates the importance of using a short-range order technique, to probe both magnetic and magnetostructural transitions and their evolution with thermal cycles.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 10