RESUMEN

Chromium-based perovskites have gained significant interest for their magnetic and ferroelectric properties. Rare-earth orthochromates are versatile multiferroic materials in catalysts, thermistors, and non-volatile memory. We present a protocol for RECrO3 crystal growth using a laser-diode floating-zone furnace. Steps include solid-phase calcination, sintering, and shaping. We provide detailed information on crystal growth parameters and Laue diffraction analysis. The successful growth of large orthochromate single crystals paves the way for exploring their intrinsic properties and potential applications. For complete details on the use and execution of this protocol, please refer to Zhu et al.1 and Zhu et al.2.

Asunto(s)

RESUMEN

We report a combined experimental and theoretical study on intriguing magnetic properties of quasiferroelectric orthochromates. Large single crystals of the family of RECrO3 (RE = Y, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) compounds were successfully grown. Neutron Laue study indicates a good quality of the obtained single crystals. Applied magnetic field and temperature dependent magnetization measurements reveal their intrinsic magnetic properties, especially the antiferromagnetic (AFM) transition temperatures. Density functional theory studies of the electronic structures were carried out using the Perdew-Burke-Ernzerhof functional plus Hubbard U method. Crystallographic information and magnetism were theoretically optimized systematically. When RE3+ cations vary from Y3+ and Eu3+ to Lu3+ ions, the calculated t-e orbital hybridization degree and Néel temperature behave similarly to the experimentally determined AFM transition temperature with variation in cationic radius. We found that the t-e hybridization is anisotropic, causing a magnetic anisotropy of Cr3+ sublattices. This was evaluated with the nearest-neighbor J 1-J 2 model. Our research provides a picture of the electronic structures during the t-e hybridization process while changing RE ions and sheds light on the nature of the weak ferromagnetism coexisting with predominated antiferromagnetism. The available large RECrO3 single crystals build a platform for further studies of orthochromates.

RESUMEN

We investigated the allotropes of tellurium under hydrostatic pressure based on density functional theory calculations and crystal structure prediction methodology. Our calculated enthalpy-pressure and energy-volume curves unveil the transition sequence from the trigonal semiconducting phase, represented by the space group P3121 in the range of 0-6 GPa, to the body centered cubic structure, space group Im3̄m, stable at 28 GPa. In between, the calculations suggest a monoclinic structure, represented by the space group C2/m and stable at 6 GPa, and the ß-Po type structure, space group R3̄m, stable at 10 GPa. The face-centered structure is found at pressure as high as 200 GPa. As the pressure is increased, the transition from the semiconducting phase to metallic phases is observed.