Impact of hydrogen absorption on crystal structure and magnetic properties of geometrically frustrated Nd2Ni2In

• Published in: Journal of alloys and compounds 2013-07, Vol.566, p.22-30
• Main Authors: Mašková, S., Havela, L., Daniš, S., Llobet, A., Nakotte, H., Kothapalli, K., Černý, R., Kolomiets, A.
• Format: Article
• Language: English
• Subjects: Antiferromagnetism; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Crystal structure; Distortion; Entropy; Exact sciences and technology; Frustration; Hydrides; Hydrogen; Hydrogen storage; Magnetic fields; Magnetic phase boundaries (including magnetic transitions, metamagnetism, etc.); Magnetic properties and materials; Magnetically ordered materials: other intrinsic properties; Magnetocaloric effect; Magnetocaloric effect, magnetic cooling; Neutron diffraction; Physics; Spin arrangements in magnetically ordered materials (including neutron and spin-polarized electron studies, synchrotron-source x-ray scattering, etc.); Structure of solids and liquids; crystallography; Structure of specific crystalline solids
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2013.02.177

•Magnetic structure of Nd2Ni2In was determined.•Nd2Ni2In can absorb up to 7H/f.u.•H absorption in relatively low H pressures leads to orthorhombic distortion.•Existence of intermediate hydrides with 2 and 4H/f.u.•4 Positions of hydrogen/deuterium were found. Nd2Ni2In orders antiferromagnetically at TN=8K. A possible first-order type of the phase transition can be related to the frustrated lattice of the Shastry–Sutherland type. The transition does not shift in magnetic field but turns into a ferromagnetic transition in magnetic fields exceeding 0.3T. Powder neutron diffraction determined the magnetic structure with Nd moments oriented mutually perpendicular along the directions of the 〈110〉 type. Large change of magnetic entropy in weak magnetic fields leads to a giant magnetocaloric effect. Reversible hydrogen absorption in pressures of several bar leads to the hydride Nd2Ni2InH≈7 achieved through the sequence of intermediate hydrides. The highest hydride has an orthorhombic distortion and volume expansion exceeding 23%. It is antiferromagnetic below TN≈3K.