Spin-Chain Incipient Magnetocaloric Effect and Rare-Earth Controlled Switching in the Haldane-Chain System, R2BaNiO5

Abstract

We have experimentally investigated the magnetocaloric effect (MCE) of a prototype spin-frustrated one-dimensional spin-chain system, the famous Haldane-chain system, R2BaNiO5 (R = Nd, Gd, Er, Dy). The significant MCE is observed far above long-range ordering, even in the paramagnetic region, which is attributed to the change in magnetic entropy due to short-range spin correlation arising from (low-dimensional) magnetic frustration. Such a spin-chain incipient MCE above long-range ordering is rarely reported. Interestingly, multiple magnetocaloric switching from conventional to inverse MCE (and vice versa) are observed below long-range magnetic ordering, as a function of temperature and magnetic field, for the R = Nd, Dy, and Er members. However, such MCE switching is absent in the Gd member, which is an S-state atom (orbital moment L = 0). Our systematic investigation of this series demonstrates that the interplay between crystal-electric field (CEF), strong spin-orbit coupling (SOC) and rare earth anisotropy of R-ions play an important role in spin reorientation, leading to multiple MCE switching due to intriguing changes in magnetic and lattice entropy. The maximum change of entropy for Er, Gd, Dy and Nd is 7.8, 6.8, 4.0 and 1.0 J Kg-1 K-1 respectively. Our study presents a pathway for tuning MCE switching and the MCE effect over large temperature regions in d-f coupled spin-frustrated and spin-chain oxide systems.

References in corpus (12)

• Inverse magnetocaloric effect in ferromagnetic Ni-Mn-Sn alloys
• Anisotropic magnetic properties and giant magnetocaloric effect in antiferromagnetic $R$MnO${}_3$ crystals ($R$=Dy, Tb, Ho and Yb)
• Enhanced magnetocaloric effect from Cr substitution in Ising lanthanide gallium garnets $L{n}_3{\text{CrGa}}_4{\text{O}}_{12}$ ($Ln$ = Tb, Dy, Ho)
• Giant magnetocaloric effect in exchange-frustrated GdCrTiO5 antiferromagnet
• Polarized-neutron study of longitudinal Haldane-gap excitations in Nd${}_2$BaNiO${}_5$
• Adiabatic demagnetization refrigeration to mK temperatures with the distorted square lattice magnet NaYbGeO${}_4$
• Geometric frustration on the trillium lattice in a magnetic metal-organic framework
• Magnetic and dielectric behavior of the spin-chain compound Er2BaNiO5 well below its Néel temperature
• Multiferroicity and magneto-electric effect in Gd${}_2$BaNiO${}_5$
• Complex nature of magnetic field-induced ferroelectricity in GdCrTiO5
• Tiny adiabatic-demagnetization refrigerator for a commercial superconducting quantum interference device magnetometer
• Intriguing Magnetocaloric Effect in Multiferroic Ba3RRu2O9 (R=Ho, Gd, Tb, Nd) with Strong 4d-4f Correlations