In recent years, ternary intermetallic compounds based on the Heusler family [1] have received considerable interest owing to their exceptional physical properties viz. high spin polarization (P) up to 100%, half-metallicity, high magnetic moment, and Curie temperature (Tc) [2, 3]. The importance of such materials relies on the fact that their physical properties are easily tunable in an unusual way for the applications in various research fields viz. spintronics [1], shape-memory [4], thermoelectrics [5], topological insulators [6], and magnetic refrigeration [7]. Moreover, recent studies have also confirmed them as potential catalysts [8]. Here, we report the first study on the synthesis and physical properties of Co2FeGe (CFG) Heusler alloy (HA) nanoparticles (NPs). The CFG-NPs of mean size 23 nm with a dispersion of ± 10 nm are prepared via the co-precipitation method. XRD and SAED patterns analysis have confirmed the cubic Heusler phase with A2-disorder. The EDAX analysis provides evidence of successful preparation of CFG-NPs and purity. These NPs are soft ferromagnetic and exhibit high saturation magnetization (Ms), and a very high Curie temperature (Tc) of 1060 K. The high Ms and Tc make the present system a potential candidate for magnetically activated nano-devices working at high temperatures. To complement our experimental results, we perform first-principles calculations. The low temperature (5 K) Ms is in close agreement with the Slater Pauling (SP) rule, which indicates that the half-metallic ferromagnetism is preserved even in particles on the 20 nm scale. Our experimental results are in close agreement with the theoretical predictions.

Theoretical and experimental investigations on Co2FeGe Heusler alloy nanoparticles for spintronics application

ACS Spring Meeting 2021

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