Vorschau

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Abstract

This work presents the high-pressure single crystal growth and the magnetic properties of the rare-earth indates GdInO3 and TbInO3, the Ruddlesden-Popper trilayer nickelates La4Ni3O10, as well as the rare-earth orthochromites ErCrO3, GdCrO3, and SmCrO3. All single crystals were grown by the floating zone method under the pressure over 20 bar. The challenges of single crystal growth are discussed and the corresponding growth parameters are presented. The magnetic properties of the materials under study are primarily characterized through magnetization measurements at temperatures down to 0.4 K and in magnetic fields up to 14 T. GdInO3 is a frustrated magnet which develops long-range magnetic order below TN = 2.1 K. Specifically, a broad 1/3 plateau indicative of the up-up-down spin configuration appears for magnetic fields B||c but is absent for B||ab. A discontinuous transition into a high-field phase is found and the magnetic phase diagram is established. For TbInO3, no long-range order is observed down to 1.8 K which combined with previous reports suggests a potential spin liquid ground state. The Ruddlesden-Popper nickelates La4Ni3O10 show a unique metal-to-metal transition. The different single crystal growth and post-annealing processes result in two distinct structure modifications P21/a and Bmab in which the metal-to-metal transitions occur at 136 K and 152 K, respectively. All single crystals of the rare-earth orthochromites ErCrO3, GdCrO3, and SmCrO3 exhibit significant magnetic anisotropy. ErCrO3, GdCrO3, and SmCrO3 develop long-range magnetic order below TN = 132 K, 167 K, and 192 K respectively, and the magnetization processes for different crystal-axis orientations clearly demonstrate the spin reorientation transition of these three materials. The presence of spin switching (magnetization reversal) in GdCrO3 is investigated. The work at hand illustrates that growth of novel correlated magnetic materials by means of sophisticated methods is a precondition for the detailed investigation and understanding of their magnetic properties.