Unusual first-order magnetic phase transition and large magnetocaloric effect in Nd2In

A large magnetocaloric effect with its maximum near the boiling point of natural gas occurs in a rare-earth intermetallic compound ${\mathrm{Nd}}_{2}\mathrm{In}$. While behaviors of physical properties indicate that paramagnetic-ferromagnetic transformation supporting the large magnetocaloric effect is first order in nature, temperature-dependent crystallographic study reveals no changes in lattice symmetry and lack of discontinuities either in phase volume or lattice parameters. The borderline first-order nature of phase transformation in ${\mathrm{Nd}}_{2}\mathrm{In}$ is markedly different from conventional first-order magnetic transitions occurring in other members of the family -- isostructural ${\mathrm{Pr}}_{2}\mathrm{In}$ and nonisostructural ${\mathrm{Eu}}_{2}\mathrm{In}$.