Free-energy analysis of the nonhysteretic first-order phase transition of Eu2In

Abstract

Binary intermetallic Eu2In was recently reported to exhibit a giant anhysteretic magnetocaloric effect due to a first-order magnetic phase transition between paramagnetic and ferromagnetic states. Experimentally, the transition occurs with a small phase volume change, ΔV/V, of approximately 0.1% around TC of ca. 55 K. We represent magnetic and compute magnetocaloric properties of a Eu2In compound using a microscopic description based on a model Hamiltonian that takes into account magnetic exchange and magnetoelastic interactions. In the model the thermodynamic nature of the transition is conveniently represented by a single magnetoelastic interaction parameter. A good agreement between the theoretical results and earlier published experimental data confirms the effectiveness of our approach.

Large inverse and normal magnetocaloric effects in HoBi compound with nonhysteretic first-order phase transition

“…Recently, a non-hysteretic firstorder phase transition was found in Eu 2 In compound. [18] It leads an interesting fundamental question to be raised, that is, whether a magnetoelastic FOMT occurs in HoBi without changing the symmetry. We will use the experimental results of first-principles and variable temperature XRD to explain the hysteresis-free phenomenon of HoBi in the future.…”

First- and second-order phase transitions in RE6Co2Ga (RE = Ho, Dy or Gd) cryogenic magnetocaloric materials

“…At higher temperatures, the ZFC and FC curves are well overlapped with each other for all the compounds, demonstrating no thermal hysteresis during their magnetic phase transitions. Such absence/negligible thermal hysteresis even in the first-order transformations for RE-based alloys makes these materials highly interesting from a technical point of view [49][50][51].…”

Correlating Crystallography, Magnetism, and Electronic Structure Across Anhysteretic First-Order Phase Transition in Pr2In

“…16 Those transitions can be further classified as magnetostructural, when magnetic (dis)order-order transitions take place in parallel with substantial rearrangements in chemical bonding and symmetry of the underlying crystal lattices, 17 or as magnetoelastic, when crystallographic symmetry remains invariant and bonding is preserved across the transition even though phase volume changes are, by definition, discontinuous. 18 In the majority of FOPTs, changes of order parameter that occur while a system crosses the transition region in different directions are hysteretic, [19][20][21][22] with hysteresis commonly categorized as one of two kinds. The first kind could be linked to the so-called "ergodic breaking" where a hysteretic change of an order parameter is recorded due to finite observation time on either side of the equilibrium boundary, for example, above and below the temperature at which phase transition occurs, commonly known as superheating and supercooling.…”