Magnetoelastic transition and negative thermal expansion of Fe&lt;sub&gt;2&lt;/sub&gt;Hf&lt;sub&gt;0.83&lt;/sub&gt;Ta&lt;sub&gt;0.17&lt;/sub&gt; ribbons

Shen, Q.; Zhang, F.; Dugulan, A.I.; van Dijk, N.H.; Brück, E.H.

doi:10.1016/j.scriptamat.2023.115482

Magnetoelastic transition and negative thermal expansion of Fe₂Hf_0.83Ta_0.17 ribbons

Title

Magnetoelastic transition and negative thermal expansion of Fe₂Hf_0.83Ta_0.17 ribbons

Author

Shen, Q. (TU Delft RST/Fundamental Aspects of Materials and Energy)
Zhang, F. (TU Delft RST/Fundamental Aspects of Materials and Energy)
Dugulan, A.I. (TU Delft RST/Fundamental Aspects of Materials and Energy; TU Delft RID/TS/Instrumenten groep)
van Dijk, N.H. (TU Delft RST/Fundamental Aspects of Materials and Energy)
Brück, E.H. (TU Delft RST/Fundamental Aspects of Materials and Energy)

Date

2023

Abstract

In this work, the magnetocaloric effect and negative thermal expansion in melt-spun Fe₂Hf_0.83Ta_0.17 Laves phase alloys were studied. Compared to arc-melted alloys, which undergo a first-order magnetoelastic transition from the ferromagnetic to the antiferromagnetic phase, melt-spun alloys exhibit a second-order transition. For Fe₂Hf_0.83Ta_0.17 ribbons, we observed a large volumetric coefficient of negative thermal expansion of −19 × 10⁻⁶ K⁻¹ over a wide temperature range of 197 – 297 K and a moderate adiabatic temperature change of 0.7 K at 290 K for a magnetic field change of 1.5 T. The magnetic field dependence of the transition temperature (dT_t/dµ₀H = 4.4 K/T) for the melt-spun alloy is about half that of the arc-melted alloy (8.6 K/T). The origin of second-order phase transition of the melt-spun alloy is attributed to the partially suppressed frustration effect, which is due to the atomic disorder introduced by the rapid solidification.